Module: Ruby2JS::Filter::React

Includes:
SEXP
Defined in:
lib/ruby2js/filter/react.rb

Constant Summary collapse

ReactAttrs =

list of react attributes that require special processing

%w(acceptCharset accessKey allowFullScreen
allowTransparency autoCapitalize autoComplete autoCorrect autoFocus
autoPlay autoSave cellPadding cellSpacing charSet classID className
clipPath colSpan contentEditable contextMenu crossOrigin
dangerouslySetInnerHTML dateTime encType fillOpacity fontFamily fontSize
formAction formEncType formMethod formNoValidate formTarget frameBorder
gradientTransform gradientUnits hrefLang htmlFor httpEquiv inputMode
itemID itemProp itemRef itemScope itemType keyParams keyType
marginHeight marginWidth markerEnd markerMid markerStart maxLength
mediaGroup noValidate patternContentUnits patternUnits
preserveAspectRatio radioGroup readOnly rowSpan spellCheck spreadMethod
srcDoc srcSet stopColor stopOpacity strokeDasharray strokeLinecap
strokeOpacity strokeWidth tabIndex textAnchor useMap viewBox
xlinkActuate xlinkArcrole xlinkHref xlinkRole xlinkShow xlinkTitle
xlinkType xmlBase xmlLang xmlSpace)
ReactAttrMap = 
Hash[ReactAttrs.map {|name| [name.downcase, name]

Class Method Summary collapse

Instance Method Summary collapse

Methods included from SEXP

#S, #s

Class Method Details

.genAttrs ⇒ Object

the following command can be used to generate ReactAttrs:

ruby -r ruby2js/filter/react -e "Ruby2JS::Filter::React.genAttrs"



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# File 'lib/ruby2js/filter/react.rb', line 30

def self.genAttrs
  require 'nokogumbo'
  page = 'https://facebook.github.io/react/docs/tags-and-attributes.html'
  doc = Nokogiri::HTML5.get(page)

  # delete contents of page prior to the list of supported attributes
  attrs = doc.at('a[name=supported-attributes]')
  attrs = attrs.parent while attrs and not attrs.name.start_with? 'h'
  attrs.previous_sibling.remove while attrs and attrs.previous_sibling

  # extract attribute names with uppercase chars from code and format
  attrs = doc.search('code').map(&:text).join(' ')
  attrs = attrs.split(/\s+/).grep(/[A-Z]/).sort.uniq.join(' ')
  puts "ReactAttrs = %w(#{attrs})".gsub(/(.{1,72})(\s+|\Z)/, "\\1\n")
end

Instance Method Details

#initialize(*args) ⇒ Object 



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# File 'lib/ruby2js/filter/react.rb', line 66

def initialize(*args)
  @react = nil
  @reactApply = nil
  @reactBlock = nil
  @reactClass = nil
  @react_props = []
  @react_methods = []
  @react_filter_functions = false
  @jsx = false
  super
end

#on_and_asgn(node) ⇒ Object

convert instance variables to state: “@x &&= y”



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# File 'lib/ruby2js/filter/react.rb', line 954

def on_and_asgn(node)
  return super unless @react
  return super unless node.children.first.type == :ivasgn
  on_op_asgn(node)
end

#on_begin(node) ⇒ Object

collapse consecutive setState calls into a single call



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# File 'lib/ruby2js/filter/react.rb', line 1109

def on_begin(node)
  node = super
  (node.children.length-2).downto(0) do |i|
    if \
      node.children[i].type == :send and
      node.children[i].children[0] and
      node.children[i].children[0].type == :self and
      node.children[i].children[1] == :setState and
      node.children[i].children[2].type == :hash and
      node.children[i+1].type == :send and
      node.children[i+1].children[0] and
      node.children[i+1].children[0].type == :self and
      node.children[i+1].children[1] == :setState and
      node.children[i+1].children[2].type == :hash and
      @comments[node.children[i+1]].empty?
    then
      pairs = node.children[i].children[2].children +
             node.children[i+1].children[2].children
      children = node.children.dup
      children.delete_at(i)
      children[i] = children[i].updated(nil, [
        *children[i].children[0..1],
        children[i].children[2].updated(nil, pairs)])
      node = node.updated(nil, children)
    end
  end
  node
end

#on_block(node) ⇒ Object

convert blocks to proc arguments



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# File 'lib/ruby2js/filter/react.rb', line 802

def on_block(node)
  if not @react
    # enable React filtering within React class method calls or
    # React component calls
    if \
      node.children.first == s(:const, nil, :React)
    then
      begin
        react, @react = @react, true
        return on_block(node)
      ensure
        @react = react
      end
    end
  end

  return super unless @react

  # block calls to createElement
  #
  # collect block and apply.  Intermediate representation
  # will look something like the following:
  #
  #   React.createElement(*proc {
  #     var $_ = ['tag', hash]
  #     $_.push(React.createElement(...))
  #     return $_
  #   }())
  #
  # Base Ruby2JS processing will convert the 'splat' to 'apply'
  child = node.children.first
  if \
    child.children[1] == :createElement and
    child.children[0] == s(:const, nil, :React)
  then
    begin
      reactApply, @reactApply = @reactApply, true
      params = [s(:splat, s(:send, s(:block, s(:send, nil, :proc),
        s(:args, s(:shadowarg, :$_)), s(:begin,
        s(:lvasgn, :$_, s(:array, *child.children[2..-1])),
        process(node.children[2]),
        s(:return, s(:lvar, :$_)))), :[]))]
    ensure
      @reactApply = reactApply
    end

    if reactApply
      return child.updated(:send, [s(:gvar, :$_), :push, 
        s(:send, *child.children[0..1], *params)])
    else
      return child.updated(:send, [*child.children[0..1], *params])
    end
  end

  # traverse through potential "css proxy" style method calls
  test = child.children.first
  while test and test.type == :send and not test.is_method?
    child, test = test, test.children.first
  end

  # wunderbar style calls
  if !@jsx and child.children[0] == nil and child.children[1] =~ /^_\w/
    if node.children[1].children.empty?
      # append block as a standalone proc
      block = s(:block, s(:send, nil, :proc), s(:args),
        *node.children[2..-1])
      return on_send node.children.first.updated(:send,
        [*node.children.first.children, block])
    else
      # iterate over Enumerable arguments if there are args present
      send = node.children.first.children
      return super if send.length < 3
      return process s(:block, s(:send, *send[0..1], *send[3..-1]),
        s(:args), s(:block, s(:send, send[2], :forEach),
        *node.children[1..-1]))
    end
  end

  begin
    reactBlock, @reactBlock = @reactBlock, true
    super
  ensure
    @reactBlock = reactBlock
  end
end

#on_class(node) ⇒ Object

Example conversion

before:
  (class (const nil :Foo) (const nil :React) nil)
after:
  (casgn nil :foo, (send :React :createClass (hash (sym :displayName)
     (:str, "Foo"))))



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# File 'lib/ruby2js/filter/react.rb', line 104

def on_class(node)
  cname, inheritance, *body = node.children
  return super unless cname.children.first == nil
  return super unless inheritance == s(:const, nil, :React) or
    inheritance == s(:const, nil, :Vue) or
    inheritance == s(:send, s(:const, nil, :React), :Component)

  # traverse down to actual list of class statements
  if body.length == 1
    if not body.first
      body = []
    elsif body.first.type == :begin
      body = body.first.children
    end
  end

  # abort conversion unless all body statements are method definitions
  return super unless body.all? do |child|
    child.type == :def or
    (child.type == :defs and child.children.first == s(:self))
  end

  begin
    react, @react = @react, true
    reactClass, @reactClass = @reactClass, true

    pairs = []

    unless es2015
      # automatically capture the displayName for the class
      pairs << s(:pair, s(:sym, :displayName),
        s(:str, cname.children.last.to_s))
    end

    # collect static properties/functions
    statics = []
    body.select {|child| child.type == :defs}.each do |child|
      _parent, mname, args, *block = child.children
      if es2015
        block = [s(:autoreturn, *block)] unless child.is_method?
        pairs << s(:defs, s(:self), mname, args, *block)
      elsif child.is_method?
        statics << s(:pair, s(:sym, mname), process(child.updated(:block,
          [s(:send, nil, :proc), args, s(:autoreturn, *block)])))
      elsif \
        block.length == 1 and
        Converter::EXPRESSIONS.include? block.first.type
      then
        statics << s(:pair, s(:sym, mname), *block)
      else
        statics << s(:pair, s(:prop, mname), {get: child.updated(
          :block, [s(:send, nil, :proc), args, s(:autoreturn, *block)])})
      end
    end

	  # collect instance methods (including getters and setters)
    @react_props = []
    @react_methods = []
	  body.each do |statement|
	    if statement.type == :def
 method = statement.children.first
 unless method == :initialize
		if method.to_s.end_with? '='
		  method = method.to_s[0..-2].to_sym
		  @react_props << method unless @react_props.include? method
		elsif statement.is_method?
		  @react_methods << method unless @react_methods.include? method
		else
		  @react_props << method unless @react_props.include? method
		end
 end
	    end
	  end

    # append statics (if any)
    unless statics.empty?
      pairs << s(:pair, s(:sym, :statics), s(:hash, *statics))
    end

    # create a default getInitialState method if there is no such method
    # and there are references to instance variables.
    if \
      not es2015 and
      not body.any? do |child|
        child.type == :def and
        [:getInitialState, :initialize].include? child.children.first
      end
    then
      @reactIvars = {pre: [], post: [], asgn: [], ref: [], cond: []}
      react_walk(node)
      unless @reactIvars.values.flatten.empty?
        body = [s(:def, :getInitialState, s(:args),
          s(:return, s(:hash))), *body]
      end
    end

    # add a proc/function for each method
    body.select {|child| child.type == :def}.each do |child|
      mname, args, *block = child.children
      @reactMethod = mname
      @reactProps = child.updated(:attr, [s(:self), :props])

      # analyze ivar usage
      @reactIvars = {pre: [], post: [], asgn: [], ref: [], cond: []}
      react_walk(child) unless mname == :initialize
      @reactIvars[:capture] =
        (@reactIvars[:pre] + @reactIvars[:post]).uniq

      if mname == :initialize
        mname = es2015 ? :initialize : :getInitialState

        # extract real list of statements
        if block.length == 1
          if not block.first
            block = []
          elsif block.first.type == :begin
            block = block.first.children
          end
        end

        # peel off the initial set of instance variable assignment stmts
        assigns = []
        block = block.dup
        while not block.empty? and block.first.type == :ivasgn
          node = block.shift
          vars = [node.children.first]
          while node.children[1].type == :ivasgn
            node = node.children[1]
            vars << node.children.first
          end
          vars.each do |var|
            assigns << s(:ivasgn, var, node.children.last)
          end
        end

        # build a hash for state
        state = s(:hash, *assigns.map {|anode| s(:pair, s(:str,
          anode.children.first.to_s[1..-1]), anode.children.last)})

        # modify block to build and/or return state
        if mname == :initialize
          block.unshift(s(:send, s(:self), :state=, state))
        elsif block.empty?
          block = [s(:return, state)]
        else
          block.unshift(s(:send, s(:self), :state=, state))
          block.push(s(:return, s(:attr, s(:self), :state)))
        end

      elsif mname == :render
        if \
           block.length != 1 or not block.last or
          not [:send, :block].include? block.last.type
        then
          if @jsx
            while block.length == 1 and block.first.type == :begin
              block = block.first.children.dup
            end

            # gather non-element emitting statements in the front
            prolog = []
            while not block.empty? and 
              react_wunderbar_free([block.first]) do
              prolog << process(block.shift)
            end

            # wrap multi-line blocks with an empty element
            block = [*prolog, s(:return,
              s(:xnode, '', *process_all(block)))]
          else
            # wrap multi-line blocks with a 'span' element
            block = [s(:return,
              s(:block, s(:send, nil, :_span), s(:args), *block))]
          end
        end

      elsif mname == :componentWillReceiveProps
        if args.children.length == 0
          args = s(:args, s(:arg, :"$$props"))
          comments = @comments[child]
          child = child.updated(:def, [mname, args, *block])
          @comments[child] = comments unless comments.empty?
          @reactProps = s(:lvar, :"$$props")
        else
          @reactProps = s(:lvar, args.children.first.children.last)
        end
      end

      # capture and update ivars as required
      block = react_process_ivars(block)

      # add method to class
      type = (child.is_method? ? :begin : :autoreturn)
      type = :begin if mname == :initialize
      if block.length == 1 and Parser::AST::Node === block.first
        type = :begin if block.first.type == :return
      end

      if es2015
        pairs << s(:def, mname, args,  process(s(type, *block)))
      else
        pairs << s(:pair, s(:sym, mname), child.updated(:block,
          [s(:send, nil, :proc), args, process(s(type, *block))]))
      end

      # retain comment
      unless @comments[child].empty?
        @comments[pairs.last] = @comments[child]
      end
    end
  ensure
    @react = react
    @reactClass = reactClass
    @reactMethod = nil
  end

  if es2015
    # emit a class that extends React.Component
    node.updated(:class, [s(:const, nil, cname.children.last),
      s(:attr, s(:const, nil, :React), :Component), *pairs]) 
  else
    # emit a createClass statement
    node.updated(:casgn, [nil, cname.children.last,
      s(:send, s(:const, nil, :React), :createClass, s(:hash, *pairs))])
  end
end

#on_cvar(node) ⇒ Object

convert class variables to props



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# File 'lib/ruby2js/filter/react.rb', line 990

def on_cvar(node)
  return super unless @reactMethod
  s(:attr, @reactProps, node.children.first.to_s[2..-1])
end

#on_cvasgn(node) ⇒ Object

prevent attempts to assign to React properties

Raises:



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# File 'lib/ruby2js/filter/react.rb', line 941

def on_cvasgn(node)
  return super unless @reactMethod
  raise Error.new("setting a React property", node)
end

#on_defs(node) ⇒ Object 



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# File 'lib/ruby2js/filter/react.rb', line 1138

def on_defs(node)
  return super unless @react

  begin
    reactIvars = @reactIvars
    @reactIvars = {pre: [], post: [], asgn: [], ref: [], cond: []}
    react_walk(node.children.last)
    @reactIvars[:capture] = (@reactIvars[:pre] + @reactIvars[:post]).uniq
    node = super
    block = react_process_ivars([node.children.last.dup])
    node.updated(nil, [*node.children[0..-2], s(:begin, *block)])
  ensure
    @reactIvars = reactIvars
  end
end

#on_gvar(node) ⇒ Object

convert global variables to refs



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# File 'lib/ruby2js/filter/react.rb', line 889

def on_gvar(node)
  return super unless @reactClass
  s(:attr, s(:attr, s(:self), :refs), node.children.first.to_s[1..-1])
end

#on_ivar(node) ⇒ Object

convert instance variables to state



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# File 'lib/ruby2js/filter/react.rb', line 895

def on_ivar(node)
  return super unless @reactClass
  if @reactMethod and @reactIvars[:capture].include? node.children.first
    node.updated(:lvar, ["$#{node.children.first[1..-1]}"])
  else
    node.updated(:attr, [s(:attr, s(:self), :state),
      node.children.first.to_s[1..-1]])
  end
end

#on_ivasgn(node) ⇒ Object

convert instance variable assignments to setState calls



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# File 'lib/ruby2js/filter/react.rb', line 906

def on_ivasgn(node)
  return super unless @react

  if @reactMethod and @reactIvars[:capture].include? node.children.first
    ivar = node.children.first.to_s
    if @reactBlock
      return s(:send, s(:self), :setState, s(:hash, s(:pair,
        s(:lvar, ivar[1..-1]), process(s(:lvasgn, "$#{ivar[1..-1]}",
        *node.children[1..-1])))))
    else
      return s(:lvasgn, "$#{ivar[1..-1]}",
        *process_all(node.children[1..-1]))
    end
  end

  vars = [node.children.first]

  while node.children.length > 1 and node.children[1].type == :ivasgn
    node = node.children[1]
    vars << node.children.first
  end

  if node.children.length == 2
    if @reactMethod == :initialize
      s(:begin, *vars.map {|var| s(:send, s(:attr, s(:self), :state),
        var.to_s[1..-1] + '=', process(node.children.last))})
    else
      s(:send, s(:self), :setState, s(:hash,
        *vars.map {|var| s(:pair, s(:str, var.to_s[1..-1]),
        process(node.children.last))}))
    end
  end
end

#on_op_asgn(node) ⇒ Object

convert instance variables to state: “@x += y”



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# File 'lib/ruby2js/filter/react.rb', line 961

def on_op_asgn(node)
  return super unless @react
  return super unless node.children.first.type == :ivasgn
  var = node.children.first.children.first
  if @reactMethod and @reactIvars[:capture].include? var
    if @reactBlock
      s(:send, s(:self), :setState, s(:hash, s(:pair,
        s(:lvar, var[1..-1]), process(s(node.type,
        s(:lvasgn, "$#{var[1..-1]}"), *node.children[1..-1])))))
    else
      process s(node.type, s(:lvasgn, "$#{var[1..-1]}"),
        *node.children[1..-1])
    end
  elsif @reactMethod == :initialize
    process s(node.type, s(:attr, s(:attr, s(:self), :state),
      var[1..-1]), *node.children[1..-1])
  elsif node.type == :or_asgn
    process s(:ivasgn, var, s(:or, s(:ivar, var),
      *node.children[1..-1]))
  elsif node.type == :and_asgn
    process s(:ivasgn, var, s(:and, s(:ivar, var),
      *node.children[1..-1]))
  else
    process s(:ivasgn, var, s(:send, s(:ivar, var),
      *node.children[1..-1]))
  end
end

#on_or_asgn(node) ⇒ Object

convert instance variables to state: “@x ||= y”



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# File 'lib/ruby2js/filter/react.rb', line 947

def on_or_asgn(node)
  return super unless @react
  return super unless node.children.first.type == :ivasgn
  on_op_asgn(node)
end

#on_pair(node) ⇒ Object

Convert hash values of type ‘lambda’ to ‘proc’. This is because Ruby ‘desugars’ -> to lambda, and Ruby2JS presumes that lambdas return a value.



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# File 'lib/ruby2js/filter/react.rb', line 1095

def on_pair(node)
  if \
    node.children[1].type == :block and
    node.children[1].children[0] == s(:send, nil, :lambda)
  then
    process node.updated(nil, [node.children[0],
      node.children[1].updated(nil, [s(:send, nil, :proc),
        *node.children[1].children[1..-1]])])
  else
    super
  end
end

#on_send(node) ⇒ Object 



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# File 'lib/ruby2js/filter/react.rb', line 331

def on_send(node)
  # convert Vue.utile.defineReactive to class fields or assignments
  if node.children.first == s(:send, s(:const, nil, :Vue), :util)
    if node.children[1] == :defineReactive
      if node.children[2].type == :cvar
        return process s(:cvasgn, node.children[2].children.first,
          node.children[3])
      elsif node.children[2].type == :send
        assign = node.children[2]
        return assign.updated(nil, [assign.children[0],
          assign.children[1].to_s + '=', node.children[3]])
      end
    end
  end

  # calls to methods (including getters) defined in this class
  if node.children[0]==nil and Symbol === node.children[1]
    if node.is_method?
      if @react_methods.include? node.children[1]
        # calls to methods defined in this class
        return node.updated nil, [s(:self), node.children[1],
          *process_all(node.children[2..-1])]
      end
    else
      if @react_props.include? node.children[1]
        # access to properties defined in this class
        return node.updated nil, [s(:self), node.children[1],
          *process_all(node.children[2..-1])]
      end
    end
  end

  if node.children.first == s(:const, nil, :Vue)
    node = node.updated(nil, [s(:const, nil, :React),
      *node.children[1..-1]])
  end

  if not @react
    # enable React filtering within React class method calls or
    # React component calls
    if \
      node.children.first == s(:const, nil, :React)
    then

      begin
        react, @react = @react, true
        return on_send(node)
      ensure
        @react = react
      end
    end
  end

  return super unless @react

  if node.children[0] == nil and node.children[1] == :_
    # text nodes
    if @reactApply
      # if apply is set, emit code that pushes text
      s(:send, s(:gvar, :$_), :push, process(node.children[2]))
    else
      # simple/normal case: simply return the text
      process(node.children[2])
    end

  elsif \
    @reactApply and node.children[1] == :createElement and
    node.children[0] == s(:const, nil, :React)
  then
    # push results of explicit calls to React.createElement
    s(:send, s(:gvar, :$_), :push, s(:send, *node.children[0..1],
      *process_all(node.children[2..-1])))

  elsif !@jsx and node.children[0] == nil and node.children[1] =~ /^_\w/
    # map method calls starting with an underscore to React calls
    # to create an element.
    #
    # input:
    #   _a 'name', href: 'link'
    # output:
    #  React.createElement("a", {href: "link"}, "name")
    #
    tag = node.children[1].to_s[1..-1]
    pairs = []
    text = block = nil
    node.children[2..-1].each do |child|
      if child.type == :hash
        # convert _ to - in attribute names
        pairs += child.children.map do |pair|
          key, value = pair.children
          if key.type == :sym
            s(:pair, s(:str, key.children[0].to_s.gsub('_', '-')), value)
          else
            pair
          end
        end

      elsif child.type == :block
        # :block arguments are inserted by on_block logic below
        block = child

      else
        # everything else added as text
        text = child
      end
    end

    # extract all class names
    classes = pairs.find_all do |pair|
      key = pair.children.first.children.first
      [:class, 'class', :className, 'className'].include? key
    end

    # combine all classes into a single value (or expression)
    if classes.length > 0
      expr = nil
      values = classes.map do |pair|
        if [:sym, :str].include? pair.children.last.type
          pair.children.last.children.first.to_s
        else
          expr = pair.children.last
          ''
        end
      end
      pairs -= classes
      if expr
        if values.length > 1
          while expr.type == :begin and expr.children.length == 1
            expr = expr.children.first
          end

          if \
            expr.type == :if and expr.children[1] and
            expr.children[1].type == :str
          then
            left = expr.children[1]
            right = expr.children[2] || s(:str, '')
            right = s(:or, right, s(:str, '')) unless right.type == :str
            expr = expr.updated(nil, [expr.children[0], left, right])
          elsif expr.type != :str
            expr = s(:or, expr, s(:str, ''))
          end

          value = s(:send, s(:str, values.join(' ')), :+, expr)
        else
          value = expr
        end
      else
        value = s(:str, values.join(' '))
      end
      pairs.unshift s(:pair, s(:sym, :className), value)
    end

    # support controlled form components
    if %w(input select textarea).include? tag
      # search for the presence of a 'value' attribute
      value = pairs.find_index do |pair|
        ['value', :value].include? pair.children.first.children.first
      end

      # search for the presence of a 'onChange' attribute
      onChange = pairs.find_index do |pair|
        ['onChange', :onChange].include? pair.children.first.children[0]
      end

      if value and pairs[value].children.last.type == :ivar and !onChange
        pairs << s(:pair, s(:sym, :onChange),
          s(:block, s(:send, nil, :proc), s(:args, s(:arg, :event)),
          s(:ivasgn, pairs[value].children.last.children.first,
          s(:attr, s(:attr, s(:lvar, :event), :target), :value))))
      end

      if not value and not onChange and tag == 'input'
        # search for the presence of a 'checked' attribute
        checked = pairs.find_index do |pair|
          ['checked', :checked].include? pair.children.first.children[0]
        end

        if checked and pairs[checked].children.last.type == :ivar
          pairs << s(:pair, s(:sym, :onChange),
            s(:block, s(:send, nil, :proc), s(:args),
            s(:ivasgn, pairs[checked].children.last.children.first,
            s(:send, pairs[checked].children.last, :!))))
        end
      end
    end

    # replace attribute names with case-sensitive javascript properties
    pairs.each_with_index do |pair, index|
      next if pair.type == :kwsplat
      name = pair.children.first.children.first.downcase
      if ReactAttrMap[name] and name.to_s != ReactAttrMap[name]
        pairs[index] = pairs[index].updated(nil, 
          [s(:str, ReactAttrMap[name]), pairs[index].children.last])
      end
    end

    # search for the presence of a 'style' attribute
    style = pairs.find_index do |pair|
      ['style', :style].include? pair.children.first.children.first
    end

    # converts style strings into style hashes
    if style and pairs[style].children[1].type == :str
      hash = []
      pairs[style].children[1].children[0].split(/;\s+/).each do |prop|
        prop.strip!
        next unless prop =~ /^([-a-z]+):\s*(.*)$/
        name, value = $1, $2
        name.gsub!(/-[a-z]/) {|str| str[1].upcase}
        if value =~ /^-?\d+$/
          hash << s(:pair, s(:str, name), s(:int, value.to_i))
        elsif value =~ /^-?\d+$\.\d*/
          hash << s(:pair, s(:str, name), s(:float, value.to_f))
        else
          hash << s(:pair, s(:str, name), s(:str, value))
        end
      end
      pairs[style] = s(:pair, pairs[style].children[0], s(:hash, *hash))
    end

    # construct hash (or nil) from pairs
    if pairs.length == 1 and pairs.first.type == :kwsplat
      hash = pairs.first.children.first
    else
      hash = (pairs.length > 0 ? process(s(:hash, *pairs)) : s(:nil))
    end

    # based on case of tag name, build a HTML tag or React component
    if tag =~ /^[A-Z]/
      params = [s(:const, nil, tag), hash]
    else
      params = [s(:str, tag), hash]
    end

    # handle nested elements
    if block
      # enable hashes to be passed as a variable on block calls
      params[-1] = text if text and params.last == s(:nil)

      # traverse down to actual list of nested statements
      args = block.children[2..-1]
      if args.length == 1
        if not args.first
          args = []
        elsif args.first.type == :begin
          args = args.first.children
        end
      end

      # check for normal case: only elements and text
      simple = args.all? do |arg|
        # explicit call to React.createElement
        next true if arg.children[1] == :createElement and
          arg.children[0] == s(:const, nil, :React)
        next true if arg.children[1] == :createElement and
          arg.children[0] == s(:const, nil, :Vue)

        # wunderbar style call
        arg = arg.children.first if arg.type == :block
        while arg.type == :send and arg.children.first != nil
          arg = arg.children.first
        end
        arg.type == :send and arg.children[1] =~ /^_/
      end

      begin
        if simple
          # in the normal case, process each argument
          reactApply, @reactApply = @reactApply, false
          params += args.map {|arg| process(arg)}
        else
          reactApply, @reactApply = @reactApply, true

          # collect children and apply.  Intermediate representation
          # will look something like the following:
          #
          #   React.createElement(*proc {
          #     var $_ = ['tag', hash]
          #     $_.push(React.createElement(...))
          #     return $_
          #   }())
          #
          # Base Ruby2JS processing will convert the 'splat' to 'apply'
          params = [s(:splat, s(:send, s(:block, s(:send, nil, :proc),
            s(:args, s(:shadowarg, :$_)), s(:begin,
            s(:lvasgn, :$_, s(:array, *params)),
            *args.map {|arg| process arg},
            s(:return, s(:lvar, :$_)))), :[]))]
        end
      ensure
        @reactApply = reactApply
      end

    elsif text
      # add text
      params << process(text)
    end

    # trim trailing null if no text or children
    params.pop if params.last == s(:nil)

    # construct element using params
    element = node.updated(:send, [s(:const, nil, :React),
      :createElement, *params])

    if @reactApply
      # if apply is set, emit code that pushes result
      s(:send, s(:gvar, :$_), :push, element)
    else
      # simple/normal case: simply return the element
      element
    end

  elsif node.children[0]==s(:send, nil, :_) and node.children[1]==:[]
    if @reactApply
      # if apply is set, emit code that pushes results
      s(:send, s(:gvar, :$_), :push, *process_all(node.children[2..-1]))
    elsif node.children.length == 3
      process(node.children[2])
    else
      # simple/normal case: simply return the element
      s(:splat, s(:array, *process_all(node.children[2..-1])))
    end

  # map method calls involving i/g/c vars to straight calls
  #
  # input:
  #   @x.(a,b,c)
  # output:
  #   @x(a,b,c)
  elsif node.children[1] == :call
    if [:ivar, :gvar, :cvar].include? node.children.first.type
      return process(s(:send, node.children.first, nil,
        *node.children[2..-1]))
    else
      return super
    end

  elsif node.children[1] == :~
    # Locate a DOM Node
    #   map ~(expression) to document.querySelector(expression)
    #   map ~name to this.refs.name
    #   map ~"a b" to document.querySelector("a b")
    #   map ~"#a" to document.getElementById("a")
    #   map ~"a" to document.getElementsByTagName("a")[0]
    #   map ~".a.b" to document.getElementsByClassName("a b")[0]
    #   map ~~expression to ~~expression
    #   map ~~~expression to ~expression

    if node.children[0] and node.children[0].type == :op_asgn
      asgn = node.children[0]
      if asgn.children[0] and asgn.children[0].type == :send
        inner = asgn.children[0]
        return on_send s(:send, s(:send, inner.children[0],
          (inner.children[1].to_s+'=').to_sym,
          s(:send, s(:send, s(:send, inner.children[0], '~'),
          *inner.children[1..-1]), *asgn.children[1..-1])), '~')
      else
        return on_send asgn.updated nil, [s(:send, asgn.children[0], '~'),
          *asgn.children[1..-1]]
      end
    end

    rewrite_tilda = proc do |tnode|
      # Example conversion:
      #   before:
      #    (send (send nil :a) :text) :~)
      #   after:
      #    (send (gvar :$a))), :text)
      if tnode.type == :send and tnode.children[0]
        if tnode.children[1] == :~ and tnode.children[0].children[1] == :~
          # consecutive tildes
          if tnode.children[0].children[0].children[1] == :~
            result = tnode.children[0].children[0].children[0]
          else
            result = s(:attr, tnode.children[0].children[0], '~')
          end
          s(:attr, s(:attr, process(result), '~'), '~')
        else
          # possible getter/setter
          method = tnode.children[1]
          method = method.to_s.chomp('=') if method =~ /=$/
          rewrite = [rewrite_tilda[tnode.children[0]],
            method, *tnode.children[2..-1]]
          rewrite[1] = tnode.children[1]
          tnode.updated nil, rewrite
        end
      elsif tnode.children.first == nil and Symbol === tnode.children[1]
        # innermost expression is a scalar
        s(:gvar, "$#{tnode.children[1]}")
      elsif tnode.type == :lvar
        s(:gvar, "$#{tnode.children[0]}")
      elsif tnode.type == :str
        if tnode.children.first =~ /^#[-\w]+$/
          s(:send, s(:attr, nil, :document), :getElementById,
            s(:str, tnode.children.first[1..-1].gsub('_', '-')))
        elsif tnode.children.first =~ /^(\.[-\w]+)+$/
          s(:send, s(:send, s(:attr, nil, :document),
            :getElementsByClassName, s(:str,
            tnode.children.first[1..-1].gsub('.', ' ').gsub('_', '-'))),
            :[], s(:int, 0))
        elsif tnode.children.first =~ /^[-\w]+$/
          s(:send, s(:send, s(:attr, nil, :document),
            :getElementsByTagName, s(:str,
            tnode.children.first.gsub('_', '-'))), :[], s(:int, 0))
        else
          s(:send, s(:attr, nil, :document), :querySelector, tnode)
        end
      else
        s(:send, s(:attr, nil, :document), :querySelector, tnode)
      end
    end

    return process rewrite_tilda[node].children[0]

  elsif node.children[0] and node.children[0].type == :send
    # determine if markaby style class and id names are being used
    child = node
    test = child.children.first
    while test and test.type == :send and not test.is_method?
      child, test = test, test.children.first
    end

    if child.children[0] == nil and child.children[1] =~ /^_\w/
      # capture the arguments provided on the current node
      children = node.children[2..-1]

      # convert method calls to id and class values
      while node != child
        if node.children[1] !~ /!$/
          # convert method name to hash {className: name} pair
          pair = s(:pair, s(:sym, :className),
            s(:str, node.children[1].to_s.gsub('_','-')))
        else
          # convert method name to hash {id: name} pair
          pair = s(:pair, s(:sym, :id),
            s(:str, node.children[1].to_s[0..-2].gsub('_','-')))
        end

        # if a hash argument is already passed, merge in id value
        hash = children.find_index {|cnode| cnode.type == :hash}
        if hash
          children[hash] = s(:hash, pair, *children[hash].children)
        else
          children.unshift s(:hash, pair)
        end

        # advance to next node
        node = node.children.first
      end

      # collapse series of method calls into a single call
      return process(node.updated(nil, [*node.children[0..1], *children]))
    else
      super
    end

  elsif \
    node.children[0] and node.children[0].type == :self and
    node.children.length == 2 and
    node.children[1] == :componentWillReceiveProps
  then
    s(:send, *node.children, s(:attr, s(:self), :props))

  else
    super
  end
end

#options=(options) ⇒ Object 



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# File 'lib/ruby2js/filter/react.rb', line 78

def options=(options)
  super
  @react = true if options[:react]
  filters = options[:filters] || Filter::DEFAULTS

  if \
    defined? Ruby2JS::Filter::Functions and
    filters.include? Ruby2JS::Filter::Functions
  then
    @react_filter_functions = true
  end

  if \
    defined? Ruby2JS::Filter::Wunderbar and
    filters.include? Ruby2JS::Filter::Wunderbar
  then
    @jsx = true
  end
end

#react_element?(node) ⇒ Boolean

is this a “wunderbar” style call or createElement?

Returns:

  • (Boolean) 


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# File 'lib/ruby2js/filter/react.rb', line 996

def react_element?(node)
  return false unless node

  forEach = [:forEach]
  forEach << :each if @react_filter_functions

  return true if node.type == :block and
    forEach.include? node.children.first.children.last and 
    react_element?(node.children.last)

  # explicit call to React.createElement
  return true if node.children[1] == :createElement and
    node.children[0] == s(:const, nil, :React)

  # explicit call to Vue.createElement
  return true if node.children[1] == :createElement and
    node.children[0] == s(:const, nil, :Vue)

  # wunderbar style call
  node = node.children.first if node.type == :block
  while node.type == :send and node.children.first != nil
    node = node.children.first
  end
  node.type == :send and node.children[1].to_s.start_with? '_'
end

#react_process_ivars(block) ⇒ Object

common logic for inserting code to manage state (ivars)



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# File 'lib/ruby2js/filter/react.rb', line 1155

def react_process_ivars(block)
  # drill down if necessary to find the block
  while block.length==1 and block.first and block.first.type==:begin
    block = block.first.children.dup
  end

  # capture ivars that are both set and referenced
  @reactIvars[:pre].uniq.sort.reverse.each do |ivar|
    block.unshift(s(:lvasgn, "$#{ivar.to_s[1..-1]}",
      s(:attr, s(:attr, s(:self), :state), ivar.to_s[1..-1])))
  end

  # update ivars that are set and later referenced
  unless @reactIvars[:post].empty?
    updates = @reactIvars[:post].uniq.sort.reverse.map do |ivar|
      s(:pair, s(:lvar, ivar.to_s[1..-1]),
        s(:lvar, "$#{ivar.to_s[1..-1]}"))
    end
    update = s(:send, s(:self), :setState, s(:hash, *updates))

    if block.last.type == :return
      block.insert(block.length-1, update)
    else
      block.push(update)
    end
  end

  block
end

#react_walk(node) ⇒ Object

analyze ivar usage



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# File 'lib/ruby2js/filter/react.rb', line 1039

def react_walk(node)
  # ignore hash values which are blocks (most typically, event handlers)
  # as these create their own scopes.
  return if node.type == :pair and node.children[0].type == :sym and
    node.children[1].type == :block
  return if node.type == :defs

  base = @reactIvars[:asgn].dup if [:if, :case].include? node.type

  node.children.each do |child|
    react_walk(child) if Parser::AST::Node === child
  end

  child = node.children.first

  case node.type
  when :if, :case
    @reactIvars[:cond] += @reactIvars[:asgn] - base

  when :ivar
    if @reactIvars[:cond].include? child
      @reactIvars[:post] << child
      @reactIvars[:pre] << child
    elsif @reactIvars[:asgn].include? child
      @reactIvars[:post] << child
      @reactIvars[:pre] << child if @reactIvars[:ref].include? child
    end
    @reactIvars[:ref] << child

  when :ivasgn
    @reactIvars[:asgn] << child

  when :op_asgn, :or_asgn, :and_asgn
    if child.type == :ivasgn
      gchild = child.children.first
      if (@reactIvars[:ref]+@reactIvars[:cond]).include? gchild
        @reactIvars[:pre] << gchild
        @reactIvars[:post] << gchild
      end
      @reactIvars[:ref] << gchild
      @reactIvars[:asgn] << gchild
    end

  when :send
    if \
      child and child.type == :self and node.children.length == 2 and
      node.children[1] == :componentWillReceiveProps
    then
      @reactIvars[:post] += @reactIvars[:asgn]
    end
  end
end

#react_wunderbar_free(nodes) ⇒ Object

ensure that there are no “wunderbar” or “createElement” calls in a set of statements.



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# File 'lib/ruby2js/filter/react.rb', line 1024

def react_wunderbar_free(nodes)
  nodes.each do |node|
    if Parser::AST::Node === node
      return false if react_element?(node)

      # recurse
      return false unless react_wunderbar_free(node.children)
    end
  end

  # no problems found
  return true
end