core-js/modules/es.string.from-code-point.js

'use strict';
var $ = require('../internals/export');
var uncurryThis = require('../internals/function-uncurry-this');
var toAbsoluteIndex = require('../internals/to-absolute-index');

var $RangeError = RangeError;
var fromCharCode = String.fromCharCode;
// eslint-disable-next-line es/no-string-fromcodepoint -- required for testing
var $fromCodePoint = String.fromCodePoint;
var join = uncurryThis([].join);

// length should be 1, old FF problem
var INCORRECT_LENGTH = !!$fromCodePoint && $fromCodePoint.length !== 1;

// `String.fromCodePoint` method
// https://tc39.es/ecma262/#sec-string.fromcodepoint
$({ target: 'String', stat: true, arity: 1, forced: INCORRECT_LENGTH }, {
  // eslint-disable-next-line no-unused-vars -- required for `.length`
  fromCodePoint: function fromCodePoint(x) {
    var elements = [];
    var length = arguments.length;
    var i = 0;
    var code;
    while (length > i) {
      code = +arguments[i++];
      if (toAbsoluteIndex(code, 0x10FFFF) !== code) throw new $RangeError(code + ' is not a valid code point');
      elements[i] = code < 0x10000
        ? fromCharCode(code)
        : fromCharCode(((code -= 0x10000) >> 10) + 0xD800, code % 0x400 + 0xDC00);
    } return join(elements, '');
  }
});