Robin E. R. Davies
69 lines
2.3 KiB
TypeScript
69 lines
2.3 KiB
TypeScript
// Copyright (c) 2022 Robin Davies
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy of
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// this software and associated documentation files (the "Software"), to deal in
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// the Software without restriction, including without limitation the rights to
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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// the Software, and to permit persons to whom the Software is furnished to do so,
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// subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO `EVENT` SHALL THE AUTHORS OR
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// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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export type OnChangedHandler<VALUE_TYPE> = (newValue: VALUE_TYPE) => void;
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export class ObservableProperty<VALUE_TYPE> {
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_value_type: VALUE_TYPE;
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_on_changed_handlers: OnChangedHandler<VALUE_TYPE>[] = [];
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constructor(default_value: VALUE_TYPE)
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{
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this._value_type = default_value;
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}
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addOnChangedHandler(handler: OnChangedHandler<VALUE_TYPE> ) : void
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{
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this._on_changed_handlers.push(handler);
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handler(this._value_type);
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}
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removeOnChangedHandler(handler: OnChangedHandler<VALUE_TYPE> ) : void
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{
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let oldArray = this._on_changed_handlers;
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let newArray: OnChangedHandler<VALUE_TYPE>[] = [];
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let outIx = 0;
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for (let i = 0; i < oldArray.length; ++i)
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{
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if (oldArray[i] !== handler)
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{
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newArray[outIx++] = oldArray[i];
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}
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}
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this._on_changed_handlers = newArray;
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}
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get() : VALUE_TYPE {
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return this._value_type;
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}
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set(value: VALUE_TYPE) : void
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{
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this._value_type = value;
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let t = this._on_changed_handlers; // take an copy in case removes happen while iteratiing.
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t.forEach(c => c(value));
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}
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}; |