Module: Preact::Component::NativeComponentConstructor

Defined in:
lib/preact/component/native_component_constructor.rb

Class Method Summary collapse

Class Method Details

.extended(base) ⇒ Object

for should_component_update we apply ruby semantics for comparing props to do so, we convert the props to ruby hashes and then compare this makes sure, that for example rubys Nil object gets handled properly



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# File 'lib/preact/component/native_component_constructor.rb', line 5

def self.extended(base)
  component_name = base.to_s
  %x{
    base.preact_component = class extends Opal.global.Preact.Component {
      constructor(props) {
        super(props);
        if (base.$default_state_defined()) {
          this.state = base.$state().$to_n();
        } else {
          this.state = {};
        };
        this.__ruby_instance = base.$new(this);
        var defined_refs = #{base.defined_refs};
        for (var ref in defined_refs) {
          if (defined_refs[ref] != null) {
            let r = ref; // to ensure closure for function below gets correct ref name
            this[ref] = function(element) {
              const oper = Opal.Preact;
              element = oper.native_element_or_component_to_ruby(element);
              oper.register_active_component(this);
              try {
                #{`this.__ruby_instance`.instance_exec(`element`, &`defined_refs[r]`)}
              } catch (e) { console.error(e.message === nil ? 'error at' : e.message, e.stack); }
              oper.unregister_active_component(this);
            }
            this[ref] = this[ref].bind(this);
          } else {
            this[ref] = Opal.global.Preact.createRef();
          }
        }
      }
      static get displayName() {
        return #{component_name};
      }
      render(props, state) {
        const oper = Opal.Preact;
        oper.render_buffer.push([]);
        oper.register_active_component(this);
        try {
          let block_result = #{`this.__ruby_instance`.instance_exec(&`base.render_block`)};
          if (block_result && block_result !== nil) { oper.render_block_result(block_result); }
        } catch (e) {
          if (oper.using_did_catch) { throw e; }
          else { console.error(e.message === nil ? 'error at' : e.message, e.stack); }
        }
        oper.unregister_active_component(this);
        let result = oper.render_buffer.pop();
        return (result.length === 1) ? result[0] : result;
      }
      shouldComponentUpdate(next_props, next_state) {
        const oper = Opal.Preact;
        if (base.should_component_update_block) {
          oper.register_active_component(this);
          let result;
          try {
            result = #{!!`this.__ruby_instance`.instance_exec(`oper.Props.$new({props: next_props})`, `oper.State.$new({state: next_state })`, &`base.should_component_update_block`)};
          } catch (e) { console.error(e.message === nil ? 'error at' : e.message, e.stack); }
          oper.unregister_active_component(this);
          return result;
        }
        if (!oper.props_are_equal(this.props, next_props)) { return true; }
        if (oper.state_is_not_equal(this.state, next_state)) { return true; }
        return false;
      }
      validateProp(props, propName, componentName) {
        try { base.$validate_prop(propName, props[propName]) }
        catch (e) { return new Error(componentName + " Error: prop validation failed: " + e.message); }
        return null;
      }
    }
  }
end