1 | class Emitter {
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2 | constructor() {
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3 | this.listeners = {};
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4 | }
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5 | addEventListener(type, callback) {
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6 | if (!(type in this.listeners)) {
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7 | this.listeners[type] = [];
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8 | }
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9 | this.listeners[type].push(callback);
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10 | }
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11 | removeEventListener(type, callback) {
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12 | if (!(type in this.listeners)) {
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13 | return;
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14 | }
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15 | const stack = this.listeners[type];
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16 | for (let i = 0, l = stack.length; i < l; i++) {
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17 | if (stack[i] === callback) {
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18 | stack.splice(i, 1);
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19 | return;
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20 | }
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21 | }
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22 | }
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23 | dispatchEvent(event) {
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24 | if (!(event.type in this.listeners)) {
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25 | return;
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26 | }
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27 | const debounce = callback => {
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28 | setTimeout(() => callback.call(this, event));
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29 | };
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30 | const stack = this.listeners[event.type];
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31 | for (let i = 0, l = stack.length; i < l; i++) {
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32 | debounce(stack[i]);
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33 | }
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34 | return !event.defaultPrevented;
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35 | }
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36 | }
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37 |
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38 | export class AbortSignal extends Emitter {
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39 | constructor() {
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40 | super();
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41 |
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42 | this.aborted = false;
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43 | this.onabort = null;
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44 | }
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45 | toString() {
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46 | return '[object AbortSignal]';
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47 | }
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48 | dispatchEvent(event) {
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49 | if (event.type === 'abort') {
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50 | this.aborted = true;
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51 | if (typeof this.onabort === 'function') {
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52 | this.onabort.call(this, event);
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53 | }
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54 | }
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55 |
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56 | super.dispatchEvent(event);
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57 | }
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58 | }
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59 |
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60 | export class AbortController {
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61 | constructor() {
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62 | this.signal = new AbortSignal();
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63 | }
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64 | abort() {
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65 | let event;
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66 | try {
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67 | event = new Event('abort');
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68 | } catch (e) {
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69 | if (typeof document !== 'undefined') {
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70 | if (!document.createEvent) {
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71 |
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72 | event = document.createEventObject();
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73 | event.type = 'abort';
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74 | } else {
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75 |
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76 | event = document.createEvent('Event');
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77 | event.initEvent('abort', false, false);
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78 | }
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79 | } else {
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80 |
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81 | event = {
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82 | type: 'abort',
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83 | bubbles: false,
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84 | cancelable: false
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85 | };
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86 | }
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87 | }
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88 | this.signal.dispatchEvent(event);
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89 | }
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90 | toString() {
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91 | return '[object AbortController]';
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92 | }
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93 | }
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94 |
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95 | export default AbortController;
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96 |
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97 | if (typeof Symbol !== 'undefined' && Symbol.toStringTag) {
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98 |
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99 |
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100 | AbortController.prototype[Symbol.toStringTag] = 'AbortController';
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101 | AbortSignal.prototype[Symbol.toStringTag] = 'AbortSignal';
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102 | }
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