40 lines
1.1 KiB
JavaScript
40 lines
1.1 KiB
JavaScript
export class TrackedState {
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constructor(callbackMethod = null, callbackScope = null) {
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this.lastSeenValue = null;
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if (callbackMethod) {
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this.callback = callbackMethod;
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if (callbackScope) {
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this.callback = this.callback.bind(callbackScope);
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}
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}
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}
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set(value, changeHandler = null, changeScope = null) {
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if (value !== this.lastSeenValue) {
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// Copy value since the changeHandler call could actually modify our lastSeenValue
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const valueCopy = value;
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this.lastSeenValue = value;
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if (changeHandler) {
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if (changeScope) {
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changeHandler.call(changeScope, valueCopy);
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} else {
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changeHandler(valueCopy);
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}
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} else if (this.callback) {
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this.callback(value);
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} else {
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assert(false, "No callback specified");
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}
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}
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}
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setSilent(value) {
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this.lastSeenValue = value;
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}
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get() {
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return this.lastSeenValue;
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}
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}
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