www.aleph1.co.uk Git - yaffs-website/blob - node_modules/string-width/index.js

   1 'use strict';
   2 var stripAnsi = require('strip-ansi');
   3 var codePointAt = require('code-point-at');
   4 var isFullwidthCodePoint = require('is-fullwidth-code-point');
   5
   6 // https://github.com/nodejs/io.js/blob/cff7300a578be1b10001f2d967aaedc88aee6402/lib/readline.js#L1345
   7 module.exports = function (str) {
   8         if (typeof str !== 'string' || str.length === 0) {
   9                 return 0;
  10         }
  11
  12         var width = 0;
  13
  14         str = stripAnsi(str);
  15
  16         for (var i = 0; i < str.length; i++) {
  17                 var code = codePointAt(str, i);
  18
  19                 // ignore control characters
  20                 if (code <= 0x1f || (code >= 0x7f && code <= 0x9f)) {
  21                         continue;
  22                 }
  23
  24                 // surrogates
  25                 if (code >= 0x10000) {
  26                         i++;
  27                 }
  28
  29                 if (isFullwidthCodePoint(code)) {
  30                         width += 2;
  31                 } else {
  32                         width++;
  33                 }
  34         }
  35
  36         return width;
  37 };