[LeetCode][JavaScript]Valid Number

https://leetcode.com/problems/valid-number/

Valid Number

Validate if a given string is numeric.

Some examples:
"0" => true
" 0.1 " => true
"abc" => false
"1 a" => false
"2e10" => true

Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.

 1 /**
 2  * @param {string} s
 3  * @return {boolean}
 4  */
 5 var isNumber = function(s) {
 6     s = s.trim();
 7     if(s !== "" && /^[-+]?(\d+\.?|\.\d+)\d*([e|E][-+]?\d+)?$/.test(s)){
 8         return true;
 9     }
10     return false;
11 };

一开始没想清楚，每多一种情况就加一个else，写的乱七八糟，后来发现都可以合并。

 1 /*
 2     s = s.trim();
 3     if(s === ""){
 4         return false;
 5     }else if(/^[-+]?[e|E]/.test(s)){
 6         return false;
 7     }else if(/^[-+]?0$/.test(s)){
 8         return true;
 9     }else if(/^[-+]?[0-9]*$/.test(s)){
10         return true;
11     }else if(/^[-+]?[0-9]+\.[0-9]*$/.test(s)){
12         return true;
13     }else if(/^[-+]?[0-9]*\.[0-9]+$/.test(s)){
14         return true;
15     }else if(/^[-+]?[0-9]*[e|E][-+]?[0-9]+$/.test(s)){
16         return true;
17     }else if(/^[-+]?([0-9]+\.[0-9]*)[e|E][-+]?[0-9]+$/.test(s)){
18         return true;
19     }else if(/^[-+]?([0-9]*\.[0-9]+)[e|E][-+]?[0-9]+$/.test(s)){
20         return true;
21     }
22     return false;
23 */