import { isObject } from './type';

/**
 * Refer: https://github.com/you-dont-need/You-Dont-Need-Lodash-Underscore
 * @param object 
 * @param keys 
 */
export function pick(object, keys:string[]) {
    return filter(object, function(acc, cur, obj) {
        return keys.indexOf(cur) != -1;
    });
}

export function filter(obj, handler?) {
    if (!isObject(obj)) {
        console.error(`Param ${obj} is not a object`);
        return {};
    }
    return Object.keys(obj).reduce((acc, cur) => {
        if (typeof handler != 'function') {
            handler = notNull;
        }
        if (handler(acc, cur, obj)) {
            return {
                ...acc,
                [cur]: obj[cur],
            };
        } else {
            return acc;
        }
    }, {});
}

function notNull(tarket, key, obj) {
    return obj[key] != null;
}

function exist(tarket, key, obj) {
    return obj[key] != null;
}

export function filterExist(obj:Object) {
    return filter(obj, exist);
}

export function map(obj, func) {
    if (!isObject(obj)) {
        console.error(`Param ${obj} is not a object`);
        return {};
    }
    return Object.keys(obj).reduce((acc, key) => {
        acc[key] = func(obj[key], key);
        return acc;
    }, {});
}

export function debounce(func, wait) {
    let timeout;
    return function (...args) {
        const context = this;
        clearTimeout(timeout);
        timeout = setTimeout(
            function() {
                func.apply(context, args)
            },
            wait
        )
    }
}