element-web/src/utils/MarkedExecution.ts
David Langley 491f0cd08a
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2024-09-09 13:57:16 +00:00

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TypeScript

/*
Copyright 2024 New Vector Ltd.
Copyright 2020 The Matrix.org Foundation C.I.C.
SPDX-License-Identifier: AGPL-3.0-only OR GPL-3.0-only
Please see LICENSE files in the repository root for full details.
*/
/**
* A utility to ensure that a function is only called once triggered with
* a mark applied. Multiple marks can be applied to the function, however
* the function will only be called once upon trigger().
*
* The function starts unmarked.
*/
export class MarkedExecution {
private marked = false;
/**
* Creates a MarkedExecution for the provided function.
* @param {Function} fn The function to be called upon trigger if marked.
* @param {Function} onMarkCallback A function that is called when a new mark is made. Not
* called if a mark is already flagged.
*/
public constructor(
private fn: () => void,
private onMarkCallback?: () => void,
) {}
/**
* Resets the mark without calling the function.
*/
public reset(): void {
this.marked = false;
}
/**
* Marks the function to be called upon trigger().
*/
public mark(): void {
if (!this.marked) this.onMarkCallback?.();
this.marked = true;
}
/**
* If marked, the function will be called, otherwise this does nothing.
*/
public trigger(): void {
if (!this.marked) return;
this.reset(); // reset first just in case the fn() causes a trigger()
this.fn();
}
}