feat(#169): add emoji support for markdown

public/script/external/marked-emoji.js

@@ -0,0 +1,57 @@
+const defaultOptions = {
+  // emojis: {}, required
+  unicode: false,
+};
+
+function markedEmoji(options) {
+  options = {
+    ...defaultOptions,
+    ...options,
+  };
+
+  if (!options.emojis) {
+    throw new Error("Must provide emojis to markedEmoji");
+  }
+
+  return {
+    extensions: [
+      {
+        name: "emoji",
+        level: "inline",
+        start(src) {
+          return src.indexOf(":");
+        },
+        tokenizer(src, tokens) {
+          const rule = /^:(.+?):/;
+          const match = rule.exec(src);
+          if (!match) {
+            return;
+          }
+
+          const name = match[1];
+          const emoji = options.emojis[name];
+
+          if (!emoji) {
+            return;
+          }
+
+          return {
+            type: "emoji",
+            raw: match[0],
+            name,
+            emoji,
+          };
+        },
+        renderer(token) {
+          if (options.unicode) {
+            return token.emoji;
+          } else {
+            return `<img class="emoji" alt="${token.name}" src="${
+              token.emoji
+            }"${this.parser.options.xhtml ? " /" : ""}>`;
+          }
+        },
+      },
+    ],
+  };
+}