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