38 lines
1.4 KiB
JavaScript
38 lines
1.4 KiB
JavaScript
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const require_toInteger = require("../util/toInteger.js");
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//#region src/compat/function/before.ts
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/**
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* Creates a function that invokes `func`, with the `this` binding and arguments
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* of the created function, while it's called less than `n` times. Subsequent
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* calls to the created function return the result of the last `func` invocation.
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*
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* @template F - The type of the function to be invoked.
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* @param {number} n - The number of times the returned function is allowed to call `func` before stopping.
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* - If `n` is 0, `func` will never be called.
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* - If `n` is a positive integer, `func` will be called up to `n-1` times.
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* @param {F} func - The function to be called with the limit applied.
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* @returns {(...args: Parameters<F>) => ReturnType<F> } - A new function that:
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* - Tracks the number of calls.
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* - Invokes `func` until the `n-1`-th call.
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* - Returns last result of `func`, if `n` is reached.
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* @throws {TypeError} - If `func` is not a function.
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* @example
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* let count = 0;
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* const before3 = before(3, () => ++count);
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*
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* before3(); // => 1
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* before3(); // => 2
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* before3(); // => 2
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*/
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function before(n, func) {
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if (typeof func !== "function") throw new TypeError("Expected a function");
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let result;
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n = require_toInteger.toInteger(n);
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return function(...args) {
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if (--n > 0) result = func.apply(this, args);
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if (n <= 1 && func) func = void 0;
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return result;
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};
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}
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//#endregion
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exports.before = before;
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