| 'use strict'; |
| |
| var $TypeError = require('es-errors/type'); |
| |
| var callBound = require('call-bound'); |
| |
| var $charCodeAt = callBound('String.prototype.charCodeAt'); |
| var $toUpperCase = callBound('String.prototype.toUpperCase'); |
| |
| // https://262.ecma-international.org/5.1/#sec-15.10.2.8 |
| |
| module.exports = function Canonicalize(ch, IgnoreCase) { |
| if (typeof ch !== 'string' || ch.length !== 1) { |
| throw new $TypeError('Assertion failed: `ch` must be a character'); |
| } |
| |
| if (typeof IgnoreCase !== 'boolean') { |
| throw new $TypeError('Assertion failed: `IgnoreCase` must be a Boolean'); |
| } |
| |
| if (!IgnoreCase) { |
| return ch; // step 1 |
| } |
| |
| var u = $toUpperCase(ch); // step 2 |
| |
| if (u.length !== 1) { |
| return ch; // step 3 |
| } |
| |
| var cu = u; // step 4 |
| |
| if ($charCodeAt(ch, 0) >= 128 && $charCodeAt(cu, 0) < 128) { |
| return ch; // step 5 |
| } |
| |
| return cu; |
| }; |