1 files changed, 26 insertions, 0 deletions
diff --git a/app/javascript/mastodon/features/emoji/unicode_to_filename.js b/app/javascript/mastodon/features/emoji/unicode_to_filename.js
new file mode 100644
index 000000000..c75c4cd7d
--- /dev/null
+++ b/app/javascript/mastodon/features/emoji/unicode_to_filename.js
@@ -0,0 +1,26 @@
+// taken from:
+// https://github.com/twitter/twemoji/blob/47732c7/twemoji-generator.js#L848-L866
+exports.unicodeToFilename = (str) => {
+  let result = '';
+  let charCode = 0;
+  let p = 0;
+  let i = 0;
+  while (i < str.length) {
+    charCode = str.charCodeAt(i++);
+    if (p) {
+      if (result.length > 0) {
+        result += '-';
+      }
+      result += (0x10000 + ((p - 0xD800) << 10) + (charCode - 0xDC00)).toString(16);
+      p = 0;
+    } else if (0xD800 <= charCode && charCode <= 0xDBFF) {
+      p = charCode;
+    } else {
+      if (result.length > 0) {
+        result += '-';
+      }
+      result += charCode.toString(16);
+    }
+  }
+  return result;
+};