Improve emoji support

src/structures/Emoji.js

@@ -101,6 +101,18 @@ class Emoji {
   toString() {
     return this.requiresColons ? `<:${this.name}:${this.id}>` : this.name;
   }
+
+  /**
+   * The identifier of this emoji, used for message reactions
+   * @readonly
+   * @type {string}
+   */
+  get identifier() {
+    if (this.id) {
+      return `${this.name}:${this.id}`;
+    }
+    return encodeURIComponent(this.name);
+  }
 }
 
 module.exports = Emoji;

src/structures/Message.js

@@ -158,7 +158,7 @@ class Message {
   }
 
   _addReaction(emoji, user) {
-    const emojiID = emoji.id || emoji;
+    const emojiID = emoji.id ? `${emoji.name}:${emoji.id}` : emoji.name;
     let reaction;
     if (this.reactions.has(emojiID)) {
       reaction = this.reactions.get(emojiID);
@@ -304,6 +304,14 @@ class Message {
   }
 
   addReaction(emoji) {
+    if (emoji.identifier) {
+      emoji = emoji.identifier;
+    } else if (typeof emoji === 'string') {
+      if (!emoji.includes('%')) emoji = encodeURIComponent(emoji);
+    } else {
+      return Promise.reject(`Emoji must be a string or an Emoji/ReactionEmoji`);
+    }
+
     return this.client.rest.methods.addMessageReaction(this.channel.id, this.id, emoji);
   }
 

src/structures/MessageReaction.js

@@ -1,5 +1,55 @@
 const Collection = require('../util/Collection');
-const parseEmoji = require('../util/ParseEmoji');
+const Emoji = require('./Emoji');
+
+/**
+ * Represents a limited emoji set used for both custom and unicode emojis. Custom emojis
+ * will use this class opposed to the Emoji class when the client doesn't know enough
+ * information about them.
+ */
+class ReactionEmoji {
+  constructor(reaction, name, id) {
+    /**
+     * The message reaction this emoji refers to
+     * @type {MessageReaction}
+     */
+    this.reaction = reaction;
+    /**
+     * The name of this reaction emoji.
+     * @type {string}
+     */
+    this.name = name;
+    /**
+     * The ID of this reaction emoji.
+     * @type {string}
+     */
+    this.id = id;
+  }
+
+  /**
+   * The identifier of this emoji, used for message reactions
+   * @readonly
+   * @type {string}
+   */
+  get identifier() {
+    if (this.id) {
+      return `${this.name}:${this.id}`;
+    }
+    return encodeURIComponent(this.name);
+  }
+
+  /**
+   * Creates the text required to form a graphical emoji on Discord.
+   * @example
+   * ```js
+   * // send the emoji used in a reaction to the channel the reaction is part of
+   * reaction.message.channel.sendMessage(`The emoji used is ${reaction.emoji}`);
+   * ```
+   * @returns {string}
+   */
+  toString() {
+    return this.id ? `<:${this.name}:${this.id}>` : this.name;
+  }
+}
 
 /**
  * Represents a reaction to a message
@@ -11,11 +61,8 @@ class MessageReaction {
      * @type {Message}
      */
     this.message = message;
-    /**
-     * The emoji of this reaction, if this is a string it is a plain unicode emoji.
-     * @type {Emoji}
-     */
-    this.emoji = emoji;
+
+    this._emoji = new ReactionEmoji(this, emoji.name, emoji.id);
     /**
      * The number of people that have given the same reaction.
      * @type {number}
@@ -28,13 +75,34 @@ class MessageReaction {
     this.users = new Collection();
   }
 
+  /**
+   * The emoji of this reaction, either an Emoji object for known custom emojis, or a ReactionEmoji which has fewer
+   * properties. Whatever the prototype of the emoji, it will still have `name`, `id`, `identifier` and `toString()`
+   * @type {Emoji|ReactionEmoji}
+   */
+  get emoji() {
+    if (this._emoji instanceof Emoji) {
+      return this._emoji;
+    }
+    // check to see if the emoji has become known to the client
+    if (this._emoji.id) {
+      const emojis = this.message.client.emojis;
+      if (emojis.has(this._emoji.id)) {
+        const emoji = emojis.get(this._emoji.id);
+        this._emoji = emoji;
+        return emoji;
+      }
+    }
+    return this._emoji;
+  }
+
   /**
    * If the client has given this reaction to a message, it is removed.
    * @returns {Promise<MessageReaction>}
    */
   remove() {
     const message = this.message;
-    return message.client.rest.methods.removeMessageReaction(message.channel.id, message.id, parseEmoji(this.emoji));
+    return message.client.rest.methods.removeMessageReaction(message.channel.id, message.id, this.emoji.identifier);
   }
 }
 

src/util/parseEmoji.js

@@ -1,4 +1,7 @@
 module.exports = function parseEmoji(text) {
+  if (text.includes('%')) {
+    text = decodeURIComponent(text);
+  }
   if (text.includes(':')) {
     const [name, id] = text.split(':');
     return { name, id };