Checks if the given argument is a number.
Use typeof
to check if a value is classified as a number primitive.
To safeguard against NaN
, check if val === val
(as NaN
has a typeof
equal to number
and is the only value not equal to itself).
代码片段
const isNumber = val => typeof val === 'number' && val === val;
使用样例
isNumber(1); // true
isNumber('1'); // false
isNumber(NaN); // false