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feat: Extend FileReader to conform with EventTarget interface #449

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feat: Extend FileReader to conform with EventTarget interface #449

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101 changes: 81 additions & 20 deletions www/FileReader.js
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Original file line number Diff line number Diff line change
Expand Up @@ -41,6 +41,10 @@ var FileReader = function () {
this._progress = null;
this._localURL = '';
this._realReader = origFileReader ? new origFileReader() : {}; // eslint-disable-line new-cap
this._listeners = {
singleEvent: {},
eventTarget: {}
};
};

/**
Expand Down Expand Up @@ -68,11 +72,60 @@ utils.defineGetter(FileReader.prototype, 'result', function () {
return this._localURL ? this._result : this._realReader.result;
});

function defineEvent (eventName) {
utils.defineGetterSetter(FileReader.prototype, eventName, function () {
return this._realReader[eventName] || null;
function listenToEvent (fileReader, eventName) {
var eventNameWithPrefix = 'on' + eventName;

if (fileReader._realReader[eventNameWithPrefix]) {
return;
}

fileReader._realReader[eventNameWithPrefix] = function () {
var args = Array.prototype.slice.call(arguments);
var listenerRunner = makeListenerRunner(args);

if (fileReader._listeners.singleEvent[eventNameWithPrefix]) {
listenerRunner(fileReader._listeners.singleEvent[eventNameWithPrefix]);
}

if (fileReader._listeners.eventTarget[eventName]) {
fileReader._listeners.eventTarget[eventName].forEach(listenerRunner);
}
};

function makeListenerRunner (args) {
return function (listener) {
setTimeout(function () {
listener.apply(fileReader, args);
});
};
}
}

function listenToEventWithPrefix (fileReader, eventNameWithPrefix) {
var eventName = eventNameWithPrefix.replace(/^on/, '');
return listenToEvent(fileReader, eventName);
}

FileReader.prototype.addEventListener = function (eventName, listener) {
var allListeners = this._listeners.eventTarget[eventName] || [];
allListeners.push(listener);
this._listeners.eventTarget[eventName] = allListeners;
listenToEvent(this, eventName);
};

FileReader.prototype.removeEventListener = function (eventName, listener) {
var allListeners = this._listeners.eventTarget[eventName] || [];
this._listeners.eventTarget[eventName] = allListeners.filter(function (currListener) {
return currListener !== listener;
});
};

function defineEvent (eventNameWithPrefix) {
utils.defineGetterSetter(FileReader.prototype, eventNameWithPrefix, function () {
return this._listeners.singleEvent[eventNameWithPrefix] || null;
}, function (value) {
this._realReader[eventName] = value;
this._listeners.singleEvent[eventNameWithPrefix] = value;
listenToEventWithPrefix(this, eventNameWithPrefix);
});
}
defineEvent('onloadstart'); // When the read starts.
Expand Down Expand Up @@ -100,8 +153,9 @@ function initRead (reader, file) {
return true;
}

if (reader.onloadstart) {
reader.onloadstart(new ProgressEvent('loadstart', {target: reader}));
var onloadstart = reader._realReader ? reader._realReader.onloadstart : reader.onloadstart;
if (onloadstart) {
onloadstart.call(reader, new ProgressEvent('loadstart', {target: reader}));
}
}

Expand Down Expand Up @@ -135,8 +189,9 @@ function readSuccessCallback (readType, encoding, offset, totalSize, accumulate,
accumulate(r);
this._progress = Math.min(this._progress + CHUNK_SIZE, totalSize);

if (typeof this.onprogress === 'function') {
this.onprogress(new ProgressEvent('progress', {loaded: this._progress, total: totalSize}));
var onprogress = this._realReader ? this._realReader.onprogress : this.onprogress;
if (typeof onprogress === 'function') {
onprogress.call(this, new ProgressEvent('progress', {loaded: this._progress, total: totalSize}));
}
}

Expand All @@ -155,12 +210,14 @@ function readSuccessCallback (readType, encoding, offset, totalSize, accumulate,
} else {
this._readyState = FileReader.DONE;

if (typeof this.onload === 'function') {
this.onload(new ProgressEvent('load', {target: this}));
var onload = this._realReader ? this._realReader.onload : this.onload;
if (typeof onload === 'function') {
onload.call(this, new ProgressEvent('load', {target: this}));
}

if (typeof this.onloadend === 'function') {
this.onloadend(new ProgressEvent('loadend', {target: this}));
var onloadend = this._realReader ? this._realReader.onloadend : this.onloadend;
if (typeof onloadend === 'function') {
onloadend.call(this, new ProgressEvent('loadend', {target: this}));
}
}
}
Expand All @@ -178,12 +235,14 @@ function readFailureCallback (e) {
this._result = null;
this._error = new FileError(e);

if (typeof this.onerror === 'function') {
this.onerror(new ProgressEvent('error', {target: this}));
var onerror = this._realReader ? this._realReader.onerror : this.onerror;
if (typeof onerror === 'function') {
onerror.call(this, new ProgressEvent('error', {target: this}));
}

if (typeof this.onloadend === 'function') {
this.onloadend(new ProgressEvent('loadend', {target: this}));
var onloadend = this._realReader ? this._realReader.onloadend : this.onloadend;
if (typeof onloadend === 'function') {
onloadend.call(this, new ProgressEvent('loadend', {target: this}));
}
}

Expand All @@ -203,12 +262,14 @@ FileReader.prototype.abort = function () {
this._readyState = FileReader.DONE;

// If abort callback
if (typeof this.onabort === 'function') {
this.onabort(new ProgressEvent('abort', {target: this}));
var onabort = this._realReader ? this._realReader.onabort : this.onabort;
if (typeof onabort === 'function') {
onabort.call(this, new ProgressEvent('abort', {target: this}));
}
// If load end callback
if (typeof this.onloadend === 'function') {
this.onloadend(new ProgressEvent('loadend', {target: this}));
var onloadend = this._realReader ? this._realReader.onloadend : this.onloadend;
if (typeof onloadend === 'function') {
onloadend.call(this, new ProgressEvent('loadend', {target: this}));
}
};

Expand Down