1 files changed, 49 insertions, 0 deletions
diff --git a/js/lib/from-code-point.js b/js/lib/from-code-point.js
new file mode 100644
index 0000000..94eca65
--- /dev/null
+++ b/js/lib/from-code-point.js
@@ -0,0 +1,49 @@
+// derived from https://github.com/mathiasbynens/String.fromCodePoint
+/*! http://mths.be/fromcodepoint v0.2.1 by @mathias */
+if (String.fromCodePoint) {
+
+  module.exports = String.fromCodePoint;
+
+} else {
+
+  var stringFromCharCode = String.fromCharCode;
+  var floor = Math.floor;
+  var fromCodePoint = function(_) {
+      var MAX_SIZE = 0x4000;
+      var codeUnits = [];
+      var highSurrogate;
+      var lowSurrogate;
+      var index = -1;
+      var length = arguments.length;
+      if (!length) {
+          return '';
+      }
+      var result = '';
+      while (++index < length) {
+          var codePoint = Number(arguments[index]);
+          if (
+              !isFinite(codePoint) || // `NaN`, `+Infinity`, or `-Infinity`
+                  codePoint < 0 || // not a valid Unicode code point
+                  codePoint > 0x10FFFF || // not a valid Unicode code point
+                  floor(codePoint) != codePoint // not an integer
+          ) {
+              return String.fromCharCode(0xFFFD);
+          }
+          if (codePoint <= 0xFFFF) { // BMP code point
+              codeUnits.push(codePoint);
+          } else { // Astral code point; split in surrogate halves
+              // http://mathiasbynens.be/notes/javascript-encoding#surrogate-formulae
+              codePoint -= 0x10000;
+              highSurrogate = (codePoint >> 10) + 0xD800;
+              lowSurrogate = (codePoint % 0x400) + 0xDC00;
+              codeUnits.push(highSurrogate, lowSurrogate);
+          }
+          if (index + 1 == length || codeUnits.length > MAX_SIZE) {
+              result += stringFromCharCode.apply(null, codeUnits);
+              codeUnits.length = 0;
+          }
+      }
+      return result;
+  };
+  module.exports = fromCodePoint;
+}