misskey/packages/backend/src/server/api/endpoints/users/groups/leave.ts

import $ from 'cafy';
import { ID } from '@/misc/cafy-id';
import define from '../../../define';
import { ApiError } from '../../../error';
import { UserGroups, UserGroupJoinings } from '@/models/index';

export const meta = {
	tags: ['groups', 'users'],

	requireCredential: true,

	kind: 'write:user-groups',

	params: {
		groupId: {
			validator: $.type(ID),
		},
	},

	errors: {
		noSuchGroup: {
			message: 'No such group.',
			code: 'NO_SUCH_GROUP',
			id: '62780270-1f67-5dc0-daca-3eb510612e31',
		},

		youAreOwner: {
			message: 'Your are the owner.',
			code: 'YOU_ARE_OWNER',
			id: 'b6d6e0c2-ef8a-9bb8-653d-79f4a3107c69',
		},
	},
} as const;

// eslint-disable-next-line import/no-default-export
export default define(meta, async (ps, me) => {
	// Fetch the group
	const userGroup = await UserGroups.findOne({
		id: ps.groupId,
	});

	if (userGroup == null) {
		throw new ApiError(meta.errors.noSuchGroup);
	}

	if (me.id === userGroup.userId) {
		throw new ApiError(meta.errors.youAreOwner);
	}

	await UserGroupJoinings.delete({ userGroupId: userGroup.id, userId: me.id });
});