顺序查找:

function seqSearch(arr, data) {for(let i = 0; i< arr.length;i++) {if(data == arr[i]) {return i;}}return -1
}
var arr=[3,44,38,5,47,15,36,26,27,2,46,4,19,50,48];
console.log(seqSearch(arr, 15))

二分查找:

function binSearch(arr, data) {let low = 0;let high = arr.length -1;while(low < high) {let middle = Math.floor((low+ high)/2);if(arr[middle] == data) {return middle} else if(arr[middle] <data) {low = middle +1;} else {high = middle -1;}}return -1;
}

参考 https://github.com/zoro-web/blog/issues/4