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e1f2e0656b
This fixes an issue when RED.events.off(..) is called in a RED.events.on(..) callback:
```
let cb = () => {
RED.events.off("event-name", cb)
....
}
RED.events.on("event-name", cb)
```
This pattern emulates a once(..), i.e., execute a callback once-only for an event.
Discussed in [Forum](https://discourse.nodered.org/t/event-offing-an-on-event-to-perform-only-once/83726)
60 lines
1.8 KiB
JavaScript
60 lines
1.8 KiB
JavaScript
/**
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* Copyright JS Foundation and other contributors, http://js.foundation
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*
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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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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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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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RED.events = (function() {
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var handlers = {};
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function on(evt,func) {
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handlers[evt] = handlers[evt]||[];
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handlers[evt].push(func);
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}
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function off(evt,func) {
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var handler = handlers[evt];
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if (handler) {
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for (var i=0;i<handler.length;i++) {
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if (handler[i] === func) {
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handler.splice(i,1);
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return;
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}
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}
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}
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}
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function emit() {
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var evt = arguments[0]
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var args = Array.prototype.slice.call(arguments,1);
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if (RED.events.DEBUG) {
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console.warn(evt,args);
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}
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if (handlers[evt]) {
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let cpyHandlers = [...handlers[evt]];
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for (var i=0;i<cpyHandlers.length;i++) {
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try {
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cpyHandlers[i].apply(null, args);
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} catch(err) {
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console.warn("RED.events.emit error: ["+evt+"] "+(err.toString()));
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console.warn(err);
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}
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}
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}
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}
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return {
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on: on,
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off: off,
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emit: emit
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}
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})();
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