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filereader.js 1.6 KB

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  1. /**
  2. * @license Copyright (c) 2003-2017, CKSource - Frederico Knabben. All rights reserved.
  3. * For licensing, see LICENSE.md.
  4. */
  5. /**
  6. * @module upload/filereader
  7. */
  8. /* globals window */
  9. import ObservableMixin from '@ckeditor/ckeditor5-utils/src/observablemixin';
  10. import mix from '@ckeditor/ckeditor5-utils/src/mix';
  11. /**
  12. * FileReader class - wrapper over native FileReader.
  13. */
  14. export default class FileReader {
  15. constructor() {
  16. const reader = new window.FileReader();
  17. /**
  18. * Instance of native FileReader.
  19. *
  20. * @private
  21. * @member {FileReader} #_reader
  22. */
  23. this._reader = reader;
  24. /**
  25. * Number of bytes loaded.
  26. *
  27. * @readonly
  28. * @observable
  29. * @member {Number} #loaded
  30. */
  31. this.set( 'loaded', 0 );
  32. reader.onprogress = evt => {
  33. this.loaded = evt.loaded;
  34. };
  35. }
  36. /**
  37. * Returns error that occurred during file reading.
  38. *
  39. * @returns {Error}
  40. */
  41. get error() {
  42. return this._reader.error;
  43. }
  44. /**
  45. * Reads provided file.
  46. *
  47. * @param {File} file Native File object.
  48. * @returns {Promise} Returns a promise that will resolve with file's contents. Promise can be rejected in case of
  49. * error or when reading process is aborted.
  50. */
  51. read( file ) {
  52. const reader = this._reader;
  53. this.total = file.size;
  54. return new Promise( ( resolve, reject ) => {
  55. reader.onload = () => {
  56. resolve( reader.result );
  57. };
  58. reader.onerror = () => {
  59. reject( 'error' );
  60. };
  61. reader.onabort = () => {
  62. reject( 'aborted' );
  63. };
  64. this._reader.readAsDataURL( file );
  65. } );
  66. }
  67. /**
  68. * Aborts file reader.
  69. */
  70. abort() {
  71. this._reader.abort();
  72. }
  73. }
  74. mix( FileReader, ObservableMixin );