Module: Opal::Nodes::Helpers

Included in:
Base
Defined in:
lib/opal/nodes/helpers.rb

Constant Summary collapse

ES51_RESERVED_WORD =

Reserved javascript keywords - we cannot create variables with the same name (ref: http://stackoverflow.com/a/9337272/601782)

/^(?:do|if|in|for|let|new|try|var|case|else|enum|eval|false|null|this|true|void|with|break|catch|class|const|super|throw|while|yield|delete|export|import|public|return|static|switch|typeof|default|extends|finally|package|private|continue|debugger|function|arguments|interface|protected|implements|instanceof)$/
ES3_RESERVED_WORD_EXCLUSIVE =

ES3 reserved words that aren’t ES5.1 reserved words

/^(?:int|byte|char|goto|long|final|float|short|double|native|throws|boolean|abstract|volatile|transient|synchronized)$/
IMMUTABLE_PROPS =

Immutable properties of the global object

/^(?:NaN|Infinity|undefined)$/
BASIC_IDENTIFIER_RULES =

Doesn't take in account utf8

/^[$_a-z][$_a-z\d]*$/i

Instance Method Summary collapse

Instance Method Details

#current_indentObject


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# File 'lib/opal/nodes/helpers.rb', line 60

def current_indent
  compiler.parser_indent
end

#empty_lineObject


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# File 'lib/opal/nodes/helpers.rb', line 69

def empty_line
  push "\n"
end

#indent(&block) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 56

def indent(&block)
  compiler.indent(&block)
end

#js_falsy(sexp) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 83

def js_falsy(sexp)
  if sexp.type == :call
    mid = sexp[2]
    if mid == :block_given?
      scope.uses_block!
      return "#{scope.block_name} === nil"
    end
  end

  with_temp do |tmp|
    [fragment("((#{tmp} = "), expr(sexp), fragment(") === nil || (#{tmp}.$$is_boolean && #{tmp} == false))")]
  end
end

#js_truthy(sexp) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 73

def js_truthy(sexp)
  if optimize = js_truthy_optimize(sexp)
    return optimize
  end

  with_temp do |tmp|
    [fragment("((#{tmp} = "), expr(sexp), fragment(") !== nil && (!#{tmp}.$$is_boolean || #{tmp} == true))")]
  end
end

#js_truthy_optimize(sexp) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 97

def js_truthy_optimize(sexp)
  if sexp.type == :call
    mid = sexp[2]

    if mid == :block_given?
      expr(sexp)
    elsif Compiler::COMPARE.include? mid.to_s
      expr(sexp)
    elsif mid == :"=="
      expr(sexp)
    end
  elsif [:lvar, :self].include? sexp.type
    [expr(sexp.dup), fragment(" !== false && "), expr(sexp.dup), fragment(" !== nil")]
  end
end

#line(*strs) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 64

def line(*strs)
  push "\n#{current_indent}"
  push(*strs)
end

#lvar_to_js(var) ⇒ Object

Converts a ruby lvar/arg name to a js identifier. Not all ruby names are valid in javascript. A $ suffix is added to non-valid names. varibales


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# File 'lib/opal/nodes/helpers.rb', line 38

def lvar_to_js(var)
  var = "#{var}$" unless valid_name? var.to_s
  var.to_sym
end

#mid_to_jsid(mid) ⇒ Object

Converts a ruby method name into its javascript equivalent for a method/function call. All ruby method names get prefixed with a '$', and if the name is a valid javascript identifier, it will have a '.' prefix (for dot-calling), otherwise it will be wrapped in brackets to use reference notation calling.


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# File 'lib/opal/nodes/helpers.rb', line 48

def mid_to_jsid(mid)
  if /\=|\+|\-|\*|\/|\!|\?|\<|\>|\&|\||\^|\%|\~|\[/ =~ mid.to_s
    "['$#{mid}']"
  else
    '.$' + mid
  end
end

#property(name) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 19

def property(name)
  valid_name?(name) ? ".#{name}" : "[#{name.inspect}]"
end

#valid_name?(name) ⇒ Boolean


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# File 'lib/opal/nodes/helpers.rb', line 23

def valid_name?(name)
  BASIC_IDENTIFIER_RULES =~ name and not(
    ES51_RESERVED_WORD          =~ name or
    ES3_RESERVED_WORD_EXCLUSIVE =~ name or
    IMMUTABLE_PROPS             =~ name
  )
end

#variable(name) ⇒ Object


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# File 'lib/opal/nodes/helpers.rb', line 31

def variable(name)
  valid_name?(name.to_s) ? name : "#{name}$"
end