first

node_modules/core-js/modules/es.string.is-well-formed.js

@@ -0,0 +1,23 @@
+'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;
+  }
+});