1 files changed, 33 insertions, 0 deletions
diff --git a/tools/eslint/node_modules/escope/node_modules/es6-map/node_modules/es5-ext/string/#/at.js b/tools/eslint/node_modules/escope/node_modules/es6-map/node_modules/es5-ext/string/#/at.js
new file mode 100644
index 0000000000..77bd251ac4
--- /dev/null
+++ b/tools/eslint/node_modules/escope/node_modules/es6-map/node_modules/es5-ext/string/#/at.js
@@ -0,0 +1,33 @@
+// Based on: https://github.com/mathiasbynens/String.prototype.at
+// Thanks @mathiasbynens !
+
+'use strict';
+
+var toInteger  = require('../../number/to-integer')
+  , validValue = require('../../object/valid-value');
+
+module.exports = function (pos) {
+	var str = String(validValue(this)), size = str.length
+	  , cuFirst, cuSecond, nextPos, len;
+	pos = toInteger(pos);
+
+	// Account for out-of-bounds indices
+	// The odd lower bound is because the ToInteger operation is
+	// going to round `n` to `0` for `-1 < n <= 0`.
+	if (pos <= -1 || pos >= size) return '';
+
+	// Second half of `ToInteger`
+	pos = pos | 0;
+	// Get the first code unit and code unit value
+	cuFirst = str.charCodeAt(pos);
+	nextPos = pos + 1;
+	len = 1;
+	if ( // check if it’s the start of a surrogate pair
+		(cuFirst >= 0xD800) && (cuFirst <= 0xDBFF) && // high surrogate
+			(size > nextPos) // there is a next code unit
+	) {
+		cuSecond = str.charCodeAt(nextPos);
+		if (cuSecond >= 0xDC00 && cuSecond <= 0xDFFF) len = 2; // low surrogate
+	}
+	return str.slice(pos, pos + len);
+};