Longest Common Prefix

LeetCode題目: 14. Longest Common Prefix

My solution:

/**
 * @param {string[]} strs
 * @return {string}
 */
let longestCommonPrefix = strs => {
    let prefix = strs[0];
    for(let idx=0; idx<strs.length; idx++) {
        while(strs[idx].indexOf(prefix) !== 0) {
            prefix = prefix.substring(0, prefix.length - 1);
        }
    }
    return prefix;
};