backport: rateLimitPerUser (#2874)

src/client/rest/RESTMethods.js

@@ -331,6 +331,8 @@ class RESTMethods {
     data.parent_id = _data.parent;
     data.permission_overwrites = _data.permissionOverwrites ?
       resolvePermissions.call(this, _data.permissionOverwrites, channel.guild) : undefined;
+    data.rate_limit_per_user = typeof _data.rateLimitPerUser !== 'undefined' ?
+      _data.rateLimitPerUser : channel.rateLimitPerUser;
     return this.rest.makeRequest('patch', Endpoints.Channel(channel), true, data, undefined, reason).then(newData =>
       this.client.actions.ChannelUpdate.handle(newData).updated
     );

src/structures/TextChannel.js

@@ -36,6 +36,12 @@ class TextChannel extends GuildChannel {
      * @type {?Snowflake}
      */
     this.lastMessageID = data.last_message_id;
+
+    /**
+     * The ratelimit per user for this channel
+     * @type {number}
+     */
+    this.rateLimitPerUser = data.rate_limit_per_user || 0;
   }
 
   /**
@@ -97,6 +103,16 @@ class TextChannel extends GuildChannel {
     }
   }
 
+  /**
+   * Sets the rate limit per user for this channel.
+   * @param {number} rateLimitPerUser The new ratelimit
+   * @param {string} [reason] Reason for changing the channel's ratelimits
+   * @returns {Promise<TextChannel>}
+   */
+  setRateLimitPerUser(rateLimitPerUser, reason) {
+    return this.edit({ rateLimitPerUser }, reason);
+  }
+
   // These are here only for documentation purposes - they are implemented by TextBasedChannel
   /* eslint-disable no-empty-function */
   send() { }