js_util

Build Status

Utilities to access JavaScript from Dart.

  • toJS(o): Converts a Dart object to a JavaScript object.
  • newObject(): Creates a new JavaScript object.
  • defineProperty(o, String prop, PropertyDescription desc): A wrapper for Object.defineProperty
  • getValue(o, String prop): Returns o[prop].
  • setValue(o, String prop, value): Performs o[prop] = value.

These utilities are of great help if a JavaScript API takes a JavaScript object with keys that are not fixed because js package does not let you create a JavaScript object without declaring a Dart class with @JS() and @anonymous.

Getting Started

Include js_util.js in index.html to use js_util functions.

<html>
  <head>
    <script async src="packages/js_util/dist/js_util.js"></script>
    <script async src="packages/browser/dart.js"></script>
  </head>
</html>

Usage

A simple usage example:

final obj = newObject();
defineProperty(obj, 'foo', new PropertyDescription(enumerable: true, value: 1));
defineProperty(obj, 'bar', new PropertyDescription(enumerable: false, value: 2));

final obj = newObject();
setValue(obj, 'foo', 1);
setValue(obj, 'bar', 2);

print(getValue(obj, 'foo')); // 1
print(getValue(obj, 'bar')); // 2

final jsObj = toJS({
  'people': [
    {'firstName': 'Kwang Yul', 'lastName': 'Seo'},
    {'firstName': 'DoHyung', 'lastName': 'Kim'},
    {'firstName': 'Kyusun', 'lastName': 'Kim'}
  ]
});

final people = getValue(jsObj, 'people');
print(getValue(people[0], 'firstName')); // 'Kwang Yul'

Features and bugs

Please file feature requests and bugs at the issue tracker.