Function once

src/platform/common/utils/functional.ts:4–19

(this: unknown, fn: T)

// Licensed under the MIT License.

export function once<T extends Function>(this: unknown, fn: T): T {
    const _this = this;
    let didCall = false;
    let result: unknown;

    return function () {
        if (didCall) {
            return result;
        }

        didCall = true;
        result = fn.apply(_this, arguments);

        return result;
    } as unknown as T;
}