signaling_server/service/node_modules/string-width/index.js

   1 'use strict';
   2 const stripAnsi = require('strip-ansi');
   3 const isFullwidthCodePoint = require('is-fullwidth-code-point');
   4 const emojiRegex = require('emoji-regex')();
   5
   6 module.exports = input => {
   7         input = input.replace(emojiRegex, '  ');
   8
   9         if (typeof input !== 'string' || input.length === 0) {
  10                 return 0;
  11         }
  12
  13         input = stripAnsi(input);
  14
  15         let width = 0;
  16
  17         for (let i = 0; i < input.length; i++) {
  18                 const code = input.codePointAt(i);
  19
  20                 // Ignore control characters
  21                 if (code <= 0x1F || (code >= 0x7F && code <= 0x9F)) {
  22                         continue;
  23                 }
  24
  25                 // Ignore combining characters
  26                 if (code >= 0x300 && code <= 0x36F) {
  27                         continue;
  28                 }
  29
  30                 // Surrogates
  31                 if (code > 0xFFFF) {
  32                         i++;
  33                 }
  34
  35                 width += isFullwidthCodePoint(code) ? 2 : 1;
  36         }
  37
  38         return width;
  39 };