utils.js 2.4 KB

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  1. /**
  2. * @license Copyright (c) 2003-2016, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md.
  4. */
  5. 'use strict';
  6. /* global console:false */
  7. import EmitterMixin from '/ckeditor5/utils/emittermixin.js';
  8. const utils = {
  9. /**
  10. * Creates an instance inheriting from {@link utils.EmitterMixin} with one additional method `observe()`.
  11. * It allows observing changes to attributes in objects being {@link utils.Observable observable}.
  12. *
  13. * The `observe()` method accepts:
  14. *
  15. * * `{String} observableName` – Identifier for the observable object. E.g. `"Editable"` when
  16. * you observe one of editor's editables. This name will be displayed on the console.
  17. * * `{utils.Observable observable} – The object to observe.
  18. * * `{Array.<String>} filterNames` – Array of propery names to be observed.
  19. *
  20. * Typical usage:
  21. *
  22. * const observer = utils.createObserver();
  23. * observer.observe( 'Editable', editor.editables.current );
  24. *
  25. * // Stop listening (method from the EmitterMixin):
  26. * observer.stopListening();
  27. *
  28. * @returns {Emitter} The observer.
  29. */
  30. createObserver() {
  31. const observer = Object.create( EmitterMixin, {
  32. observe: {
  33. value: function observe( observableName, observable, filterNames ) {
  34. observer.listenTo( observable, 'change', ( evt, propertyName, value, oldValue ) => {
  35. if ( !filterNames || filterNames.includes( propertyName ) ) {
  36. console.log( `[Change in ${ observableName }] ${ propertyName } = '${ value }' (was '${ oldValue }')` );
  37. }
  38. } );
  39. return observer;
  40. }
  41. }
  42. } );
  43. return observer;
  44. },
  45. /**
  46. * Checkes wether observable properties are properly bound to each other.
  47. *
  48. * Syntax given that observable `A` is bound to observables [`B`, `C`, ...]:
  49. *
  50. * assertBinding( A,
  51. * { initial `A` attributes },
  52. * [
  53. * [ B, { new `B` attributes } ],
  54. * [ C, { new `C` attributes } ],
  55. * ...
  56. * ],
  57. * { `A` attributes after [`B`, 'C', ...] changed }
  58. * );
  59. */
  60. assertBinding( observable, stateBefore, data, stateAfter ) {
  61. let key, pair;
  62. for ( key in stateBefore ) {
  63. expect( observable[ key ] ).to.be.equal( stateBefore[ key ] );
  64. }
  65. // Change attributes of bound observables.
  66. for ( pair of data ) {
  67. for ( key in pair[ 1 ] ) {
  68. pair[ 0 ][ key ] = pair[ 1 ][ key ];
  69. }
  70. }
  71. for ( key in stateAfter ) {
  72. expect( observable[ key ] ).to.be.equal( stateAfter[ key ] );
  73. }
  74. }
  75. };
  76. export default utils;