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util.js
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util.js
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/* Common utilities */
WaveSurfer.util = {
extend: function (dest) {
var sources = Array.prototype.slice.call(arguments, 1);
sources.forEach(function (source) {
Object.keys(source).forEach(function (key) {
dest[key] = source[key];
});
});
return dest;
},
getId: function () {
return 'wavesurfer_' + Math.random().toString(32).substring(2);
},
ajax: function (options) {
var ajax = Object.create(WaveSurfer.Observer);
var xhr = new XMLHttpRequest();
var fired100 = false;
xhr.open(options.method || 'GET', options.url, true);
xhr.responseType = options.responseType || 'json';
xhr.addEventListener('progress', function (e) {
ajax.fireEvent('progress', e);
if (e.lengthComputable && e.loaded == e.total) {
fired100 = true;
}
});
xhr.addEventListener('load', function (e) {
if (!fired100) {
ajax.fireEvent('progress', e);
}
ajax.fireEvent('load', e);
if (200 == xhr.status || 206 == xhr.status) {
ajax.fireEvent('success', xhr.response, e);
} else {
ajax.fireEvent('error', e);
}
});
xhr.addEventListener('error', function (e) {
ajax.fireEvent('error', e);
});
xhr.send();
ajax.xhr = xhr;
return ajax;
}
};
/* Observer */
WaveSurfer.Observer = {
/**
* Attach a handler function for an event.
*/
on: function (event, fn) {
if (!this.handlers) { this.handlers = {}; }
var handlers = this.handlers[event];
if (!handlers) {
handlers = this.handlers[event] = [];
}
handlers.push(fn);
// Return an event descriptor
return {
name: event,
callback: fn,
un: this.un.bind(this, event, fn)
};
},
/**
* Remove an event handler.
*/
un: function (event, fn) {
if (!this.handlers) { return; }
var handlers = this.handlers[event];
if (handlers) {
if (fn) {
for (var i = handlers.length - 1; i >= 0; i--) {
if (handlers[i] == fn) {
handlers.splice(i, 1);
}
}
} else {
handlers.length = 0;
}
}
},
/**
* Remove all event handlers.
*/
unAll: function () {
this.handlers = null;
},
/**
* Attach a handler to an event. The handler is executed at most once per
* event type.
*/
once: function (event, handler) {
var my = this;
var fn = function () {
handler.apply(this, arguments);
setTimeout(function () {
my.un(event, fn);
}, 0);
};
return this.on(event, fn);
},
fireEvent: function (event) {
if (!this.handlers) { return; }
var handlers = this.handlers[event];
var args = Array.prototype.slice.call(arguments, 1);
handlers && handlers.forEach(function (fn) {
fn.apply(null, args);
});
}
};
/* Make the main WaveSurfer object an observer */
WaveSurfer.util.extend(WaveSurfer, WaveSurfer.Observer);