1 files changed, 13 insertions, 0 deletions
diff --git a/node_modules/es-abstract/helpers/isPrefixOf.js b/node_modules/es-abstract/helpers/isPrefixOf.js
new file mode 100644
index 000000000..b67d64056
--- /dev/null
+++ b/node_modules/es-abstract/helpers/isPrefixOf.js
@@ -0,0 +1,13 @@
+'use strict';
+
+var $strSlice = require('../helpers/callBound')('String.prototype.slice');
+
+module.exports = function isPrefixOf(prefix, string) {
+	if (prefix === string) {
+		return true;
+	}
+	if (prefix.length > string.length) {
+		return false;
+	}
+	return $strSlice(string, 0, prefix.length) === prefix;
+};