firstAndLast.js

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var searchRange = function(nums, target) {
    let result = [-1,-1];
    nums.forEach((e,i) => {
        if(e <= target){
            if(e === target){
                if(result[0] === -1){
                   result[0] = i;
                   result[1] = i;
                } else {
                    result[1] = i;
                }   
            }
        } else {
            return result;
        } 
    });
    return result;
};