Some common JS programming problems

1. Implement the array Chaos sequence

var a = [1,2,3,4,5,6,7,8,9,0,12,23,45,90];a.sort (function  (A, b    ) {var sign = (Math.random () >0.5)? 1:-1;     return (A-B) * sign;});

2. Use of reduce

// there is an array of length 100, please find the sum of the first 10 elements of the array in an elegant way var b = [1,2,3,4,5,6,7,8,9,10]; var sum = B.slice (0,10). Reduce (function  (pre,cur) {    return pre + cur;}, 0);

3, there is an array of length 100, the value is the index of its location

var New Array (= A.join (","). Split (","). Map (function(item, index) {    return  Index;});

4.

Some common JS programming problems