export default class ArrayUtils {
    /**
     * 移除元素
     */
    static removeFromArr(arr: Array<any>, obj: any) {
        let index = arr.indexOf(obj);
        arr.splice(index, 1);
    }

    static randomFromArr(arr: Array<any>) {
        let index = Math.floor(Math.random() * arr.length);
        return arr[index];
    }

    /**
     * 数组随机排序
     */
    static shuffle(arr: Array<any>) {
        return arr.sort(function () {
            return Math.random() - 0.5;
        });
    }

    static indexOf(arr, callback, ctx?) {
        for (var i = 0; i < arr.length; i++) {
            if (callback.call(ctx, this[i], i))
                return i;
        }
        return -1;
    }

    static each(arr, callback, context) {
        if (typeof callback !== 'function')
            throw new TypeError();

        for (let i = 0, len = arr.length; i < len; i++) {
            if (callback.call(context, arr[i], i, arr))
                break;
        }
    }

    static async queue(arr) {
        let res = null;
        for (let promise of arr) {
            res = await promise(res)
        }
        return await res;
    }

    static getRandomArray(arr, count) {
        let shuffled = arr.slice(0);
        let len = arr.length;
        let min = len - count, temp, index;
        while (len-- > min) {
            index = Math.floor((len + 1) * Math.random());
            temp = shuffled[index];
            shuffled[index] = shuffled[len];
            shuffled[len] = temp;
        }
        return shuffled.slice(min);
    }
}