Repository: discordjs/discord.js
File: packages/discord.js/src/managers/GuildEmojiRoleManager.js (JavaScript)

Code before:
  async add(roleOrRoles) {
    let roles;
    if (!Array.isArray(roleOrRoles) && !(roleOrRoles instanceof Collection)) roles = [roleOrRoles];
    else roles = roleOrRoles;

    const resolvedRoles = [];
    for (const role of roles.values()) {
      const resolvedRole = this.guild.roles.resolveId(role);
      if (!resolvedRole) {
        throw new DiscordjsTypeError(ErrorCodes.InvalidElement, 'Array or Collection', 'roles', role);
      }
      resolvedRoles.push(resolvedRole);
    }

    const newRoles = [...new Set(resolvedRoles.concat(...this.cache.keys()))];
    return this.set(newRoles);
  }

  /**
   * Removes a role (or multiple roles) from the list of roles that can use this emoji.
   * @param {RoleResolvable|RoleResolvable[]|Collection<Snowflake, Role>} roleOrRoles The role or roles to remove
   * @returns {Promise<GuildEmoji>}
   */
  async remove(roleOrRoles) {
    let roles;
    if (!Array.isArray(roleOrRoles) && !(roleOrRoles instanceof Collection)) roles = [roleOrRoles];
    else roles = roleOrRoles;

    const resolvedRoleIds = [];
    for (const role of roles.values()) {
      const roleId = this.guild.roles.resolveId(role);
      if (!roleId) {
        throw new DiscordjsTypeError(ErrorCodes.InvalidElement, 'Array or Collection', 'roles', role);
      }
      resolvedRoleIds.push(roleId);
    }

    const newRoles = [...this.cache.keys()].filter(id => !resolvedRoleIds.includes(id));
    return this.set(newRoles);
  }

  /**
   * Sets the role(s) that can use this emoji.
   * @param {Collection<Snowflake, Role>|RoleResolvable[]} roles The roles or role ids to apply
   * @returns {Promise<GuildEmoji>}
   * @example
   * // Set the emoji's roles to a single role
   * guildEmoji.roles.set(['391156570408615936'])
   *   .then(console.log)
   *   .catch(console.error);
   * @example

Review comment (suggestion):
```suggestion
    if (Array.isArray(roleOrRoles) || roleOrRoles instanceof Collection) roles = roleOrRoles;
```

Code after:
  async add(roleOrRoles) {
    const roles = Array.isArray(roleOrRoles) || roleOrRoles instanceof Collection ? roleOrRoles : [roleOrRoles];

    const resolvedRoleIds = [];
    for (const role of roles.values()) {
      const roleId = this.guild.roles.resolveId(role);
      if (!roleId) {
        throw new DiscordjsTypeError(ErrorCodes.InvalidElement, 'Array or Collection', 'roles', role);
      }
      resolvedRoleIds.push(roleId);
    }

    const newRoles = [...new Set(resolvedRoleIds.concat(...this.cache.keys()))];
    return this.set(newRoles);
  }

  /**
   * Removes a role (or multiple roles) from the list of roles that can use this emoji.
   * @param {RoleResolvable|RoleResolvable[]|Collection<Snowflake, Role>} roleOrRoles The role or roles to remove
   * @returns {Promise<GuildEmoji>}
   */
  async remove(roleOrRoles) {
    const roles = Array.isArray(roleOrRoles) || roleOrRoles instanceof Collection ? roleOrRoles : [roleOrRoles];

    const resolvedRoleIds = [];
    for (const role of roles.values()) {
      const roleId = this.guild.roles.resolveId(role);
      if (!roleId) {
        throw new DiscordjsTypeError(ErrorCodes.InvalidElement, 'Array or Collection', 'roles', role);
      }
      resolvedRoleIds.push(roleId);
    }

    const newRoles = [...this.cache.keys()].filter(id => !resolvedRoleIds.includes(id));
    return this.set(newRoles);
  }

  /**
   * Sets the role(s) that can use this emoji.
   * @param {Collection<Snowflake, Role>|RoleResolvable[]} roles The roles or role ids to apply
   * @returns {Promise<GuildEmoji>}
   * @example
   * // Set the emoji's roles to a single role
   * guildEmoji.roles.set(['391156570408615936'])
   *   .then(console.log)
   *   .catch(console.error);
   * @example
   * // Remove all roles from an emoji
   * guildEmoji.roles.set([])
   *    .then(console.log)
   *    .catch(console.error);