24 lines
868 B
JavaScript
24 lines
868 B
JavaScript
'use strict';
|
|
var $ = require('../internals/export');
|
|
var uncurryThis = require('../internals/function-uncurry-this');
|
|
var requireObjectCoercible = require('../internals/require-object-coercible');
|
|
var toString = require('../internals/to-string');
|
|
|
|
var charCodeAt = uncurryThis(''.charCodeAt);
|
|
|
|
// `String.prototype.isWellFormed` method
|
|
// https://github.com/tc39/proposal-is-usv-string
|
|
$({ target: 'String', proto: true }, {
|
|
isWellFormed: function isWellFormed() {
|
|
var S = toString(requireObjectCoercible(this));
|
|
var length = S.length;
|
|
for (var i = 0; i < length; i++) {
|
|
var charCode = charCodeAt(S, i);
|
|
// single UTF-16 code unit
|
|
if ((charCode & 0xF800) !== 0xD800) continue;
|
|
// unpaired surrogate
|
|
if (charCode >= 0xDC00 || ++i >= length || (charCodeAt(S, i) & 0xFC00) !== 0xDC00) return false;
|
|
} return true;
|
|
}
|
|
});
|