da569c2c8d
constantTimeDispatcher lets you poke a specific react component to do something without having to do any O(N) operations. This is useful if you have thousands of RoomTiles in a RoomSubList and want to just tell one of them to update, without either having to do a full comparison of this.props.list or have each and every RoomTile subscribe to a generic event from flux or node's eventemitter *UNTESTED*
62 lines
2.2 KiB
JavaScript
62 lines
2.2 KiB
JavaScript
/*
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Copyright 2017 Vector Creations Ltd
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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// singleton which dispatches invocations of a given type & argument
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// rather than just a type (as per EventEmitter and Flux's dispatcher etc)
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//
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// This means you can have a single point which listens for an EventEmitter event
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// and then dispatches out to one of thousands of RoomTiles (for instance) rather than
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// having each RoomTile register for the EventEmitter event and having to
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// iterate over all of them.
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class ConstantTimeDispatcher {
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constructor() {
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// type -> arg -> [ listener(arg, params) ]
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this.listeners = {};
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}
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register(type, arg, listener) {
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if (!this.listeners[type]) this.listeners[type] = {};
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if (!this.listeners[type][arg]) this.listeners[type][arg] = [];
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this.listeners[type][arg].push(listener);
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}
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unregister(type, arg, listener) {
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if (this.listeners[type] && this.listeners[type][arg]) {
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var i = this.listeners[type][arg].indexOf(listener);
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if (i > -1) {
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this.listeners[type][arg].splice(i, 1);
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}
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}
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else {
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console.warn("Unregistering unrecognised listener (type=" + type + ", arg=" + arg + ")");
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}
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}
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dispatch(type, arg, params) {
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if (!this.listeners[type] || !this.listeners[type][arg]) {
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console.warn("No registered listeners for dispatch (type=" + type + ", arg=" + arg + ")");
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return;
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}
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this.listeners[type][arg].forEach(listener=>{
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listener.call(arg, params);
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});
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}
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}
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if (!global.constantTimeDispatcher) {
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global.constantTimeDispatcher = new ConstantTimeDispatcher();
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}
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module.exports = global.constantTimeDispatcher;
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