add script that builds shortname-indexed json for each skin tone

build/generate-reverse-map.php

@@ -0,0 +1,40 @@
+<?php
+// build the reverse mapping arrays for each skin variation 
+
+$emoji_data = json_decode(file_get_contents('https://raw.githubusercontent.com/iamcal/emoji-data/master/emoji_pretty.json'), true);
+
+$map = [];
+
+$skin_tones = array(
+    '1F3FB' => 'skin-tone-2',
+    '1F3FC' => 'skin-tone-3',
+    '1F3FD' => 'skin-tone-4',
+    '1F3FE' => 'skin-tone-5',
+    '1F3FF' => 'skin-tone-6',
+);
+
+foreach($emoji_data as $emoji) {
+    foreach ($emoji['short_names'] as $short_name) {
+        $map['unified'][$short_name] = $emoji['unified'];
+        foreach($skin_tones as $code => $type) {
+            $map[$type][$short_name] = $emoji['unified'];
+        }
+
+        if(isset($emoji['skin_variations'])) {
+            foreach($emoji['skin_variations'] as $key => $var) {
+                if (isset($skin_tones[$key])) {
+                    $type = $skin_tones[$key];
+                } else if (isset($skin_tones[$key . '-' . $key])) {
+                    $type = $skin_tones[$key . '-' . $key];
+                } else {
+                    continue;
+                }
+                $map[$type][$short_name] = $var['unified'];
+            }
+        }
+    }
+}
+
+foreach ($map as $type => $data) {
+    file_put_contents(dirname(__FILE__).'/../src/map-reverse-' . $type . '.json', json_encode($data, JSON_PRETTY_PRINT));
+}