add node modules to repo

node_modules/truncate-utf8-bytes/lib/truncate.js

@@ -0,0 +1,43 @@
+'use strict';
+
+function isHighSurrogate(codePoint) {
+  return codePoint >= 0xd800 && codePoint <= 0xdbff;
+}
+
+function isLowSurrogate(codePoint) {
+  return codePoint >= 0xdc00 && codePoint <= 0xdfff;
+}
+
+// Truncate string by size in bytes
+module.exports = function truncate(getLength, string, byteLength) {
+  if (typeof string !== "string") {
+    throw new Error("Input must be string");
+  }
+
+  var charLength = string.length;
+  var curByteLength = 0;
+  var codePoint;
+  var segment;
+
+  for (var i = 0; i < charLength; i += 1) {
+    codePoint = string.charCodeAt(i);
+    segment = string[i];
+
+    if (isHighSurrogate(codePoint) && isLowSurrogate(string.charCodeAt(i + 1))) {
+      i += 1;
+      segment += string[i];
+    }
+
+    curByteLength += getLength(segment);
+
+    if (curByteLength === byteLength) {
+      return string.slice(0, i + 1);
+    }
+    else if (curByteLength > byteLength) {
+      return string.slice(0, i - segment.length + 1);
+    }
+  }
+
+  return string;
+};
+