Function createOrUpdate

src/util/throttle.ts:141–171

(
    obj: T,
    fnAttr: S,
    rate: number,
    throttleType: ThrottleType
)

 *
 */
export function createOrUpdate<T, S extends keyof T, P = T[S]>(
    obj: T,
    fnAttr: S,
    rate: number,
    throttleType: ThrottleType
): P extends ThrottleFunction ? P & ThrottleController : never {
    let fn = obj[fnAttr];

    if (!fn) {
        return;
    }

    const originFn = (fn as any)[ORIGIN_METHOD] || fn;
    const lastThrottleType = (fn as any)[THROTTLE_TYPE];
    const lastRate = (fn as any)[RATE];

    if (lastRate !== rate || lastThrottleType !== throttleType) {
        if (rate == null || !throttleType) {
            return (obj[fnAttr] = originFn);
        }

        fn = obj[fnAttr] = throttle(
            originFn, rate, throttleType === 'debounce'
        );
        (fn as any)[ORIGIN_METHOD] = originFn;
        (fn as any)[THROTTLE_TYPE] = throttleType;
        (fn as any)[RATE] = rate;
    }

    return fn as ReturnType<typeof createOrUpdate>;
}

/**
 * Clear throttle. Example see throttle.createOrUpdate.