import { done } from './util';
function decorate(decorator: (fn: Function, key: string) => Function): Function {
return function (original: any, context: ClassMethodDecoratorContext) {
if (context.kind === 'method' || context.kind === 'getter' || context.kind === 'setter') {
return decorator(original, context.name.toString());
}
throw new Error('not supported');
};
}
function _memoize(fn: Function, key: string): Function {
const memoizeKey = `$memoize$${key}`;
return function (this: any, ...args: any[]) {
if (!this.hasOwnProperty(memoizeKey)) {
Object.defineProperty(this, memoizeKey, {
configurable: false,
enumerable: false,
writable: false,
value: fn.apply(this, args)
});
}
return this[memoizeKey];
};
}
export const memoize = decorate(_memoize);
function _throttle<T>(fn: Function, key: string): Function {
const currentKey = `$throttle$current$${key}`;
const nextKey = `$throttle$next$${key}`;
const trigger = function (this: any, ...args: any[]) {
if (this[nextKey]) {
return this[nextKey];
}
if (this[currentKey]) {
this[nextKey] = done(this[currentKey]).then(() => {
this[nextKey] = undefined;
return trigger.apply(this, args);
});
return this[nextKey];
}
this[currentKey] = fn.apply(this, args) as Promise<T>;
const clear = () => this[currentKey] = undefined;
done(this[currentKey]).then(clear, clear);
return this[currentKey];
};
return trigger;
}
export const throttle = decorate(_throttle);
function _sequentialize(fn: Function, key: string): Function {
const currentKey = `__$sequence$${key}`;
return function (this: any, ...args: any[]) {
const currentPromise = this[currentKey] as Promise<any> || Promise.resolve(null);
const run = async () => await fn.apply(this, args);
this[currentKey] = currentPromise.then(run, run);
return this[currentKey];
};
}
export const sequentialize = decorate(_sequentialize);
export function debounce(delay: number): Function {
return decorate((fn, key) => {
const timerKey = `$debounce$${key}`;
return function (this: any, ...args: any[]) {
clearTimeout(this[timerKey]);
this[timerKey] = setTimeout(() => fn.apply(this, args), delay);
};
});
}
