58 lines
1.5 KiB
React
58 lines
1.5 KiB
React
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class EventEmitter
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{
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//--------------------------
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// constructor
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//--------------------------
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constructor()
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{
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this.listeners = new Map();
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}
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//--------------------------
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// methods
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//--------------------------
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addListener(label, callback) {
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this.listeners.has(label) || this.listeners.set(label, []);
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this.listeners.get(label).push(callback);
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}
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removeListener(label, callback) {
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var isFunction = function(obj) {
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return typeof obj == 'function' || false;
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};
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var listeners = this.listeners.get(label),
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index;
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if (listeners && listeners.length) {
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index = listeners.reduce((i, listener, index) => {
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return (isFunction(listener) && listener === callback)
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? i = index
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: i;
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}, -1);
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if (index > -1) {
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listeners.splice(index, 1);
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this.listeners.set(label, listeners);
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return true;
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}
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}
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return false;
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}
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emitEvent(label, ...args) {
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var listeners = this.listeners.get(label);
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if (listeners && listeners.length) {
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listeners.forEach((listener) => {
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listener(...args);
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});
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return true;
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}
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return false;
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}
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//--------------------------
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// event handlers
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//--------------------------
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}
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export default EventEmitter
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