is-fullwidth-code-point 
Check if the character represented by a given Unicode code point is fullwidth
Install
$ npm install is-fullwidth-code-point
Usage
const isFullwidthCodePoint = require('is-fullwidth-code-point');
isFullwidthCodePoint('谢'.codePointAt(0));
//=> true
isFullwidthCodePoint('a'.codePointAt(0));
//=> false
API
isFullwidthCodePoint(codePoint)
codePoint
Type: number
The code point of a character.
License
MIT © Sindre Sorhus