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#65 - Valid Number
Problem Description
Given a string s, return whether s is a valid number.
For example, all the following are valid numbers: "2", "0089", "-0.1", "+3.14", "4.", "-.9", "2e10", "-90E3", "3e+7", "+6e-1", "53.5e93", "-123.456e789", while the following are not valid numbers: "abc", "1a", "1e", "e3", "99e2.5", "--6", "-+3", "95a54e53".
Formally, a valid number is defined using one of the following definitions:
- An integer number followed by an optional exponent.
- A decimal number followed by an optional exponent.
An integer number is defined with an optional sign '-' or '+' followed by digits.
A decimal number is defined with an optional sign '-' or '+' followed by one of the following definitions:
- Digits followed by a dot '.'.
- Digits followed by a dot '.' followed by digits.
- A dot '.' followed by digits.
- An exponent is defined with an exponent notation 'e' or 'E' followed by an integer number.
The digits are defined as one or more digits.
Solution
/**
* @param {string} s
* @return {boolean}
*/
var isNumber = function(s) {
return s.trim().length && !isNaN(s.trim()) && !s.includes('Infinity');
};