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59 lines
1.8 KiB
TypeScript
59 lines
1.8 KiB
TypeScript
/*
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Copyright 2020 The Matrix.org Foundation C.I.C.
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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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/**
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* A utility to ensure that a function is only called once triggered with
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* a mark applied. Multiple marks can be applied to the function, however
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* the function will only be called once upon trigger().
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*
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* The function starts unmarked.
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*/
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export class MarkedExecution {
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private marked = false;
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/**
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* Creates a MarkedExecution for the provided function.
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* @param {Function} fn The function to be called upon trigger if marked.
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* @param {Function} onMarkCallback A function that is called when a new mark is made. Not
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* called if a mark is already flagged.
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*/
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constructor(private fn: () => void, private onMarkCallback?: () => void) {
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}
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/**
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* Resets the mark without calling the function.
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*/
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public reset() {
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this.marked = false;
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}
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/**
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* Marks the function to be called upon trigger().
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*/
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public mark() {
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if (!this.marked) this.onMarkCallback?.();
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this.marked = true;
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}
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/**
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* If marked, the function will be called, otherwise this does nothing.
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*/
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public trigger() {
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if (!this.marked) return;
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this.reset(); // reset first just in case the fn() causes a trigger()
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this.fn();
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}
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}
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