@molecule/api-resource-follow

Auto-generated, AI-first package reference for the molecule.dev ecosystem. It is written to be read by coding agents as much as by people, and is generated from this package's source — edit src/index.ts JSDoc, not this file.

Follow/unfollow resource for molecule.dev.

Polymorphic follow system for users or any resource type. Supports followers list, following list, and follow status checks.

Quick Start

import { routes, requestHandlerMap } from '@molecule/api-resource-follow'

// Wire routes into your Express app via mlcl inject
// POST   /follow/:targetType/:targetId
// DELETE /follow/:targetType/:targetId
// GET    /:targetType/:targetId/followers
// GET    /following
// GET    /follow/check/:targetType/:targetId

Type

resource

Installation

npm install @molecule/api-resource-follow @molecule/api-database @molecule/api-i18n @molecule/api-logger @molecule/api-resource

API

Interfaces

Follow

A follow relationship between a user and a target resource.

interface Follow {
  /** Unique follow identifier. */
  id: string
  /** The ID of the user who is following. */
  followerId: string
  /** The type of target being followed (e.g. 'user', 'project'). */
  targetType: string
  /** The ID of the target being followed. */
  targetId: string
  /** When the follow was created (ISO 8601). */
  createdAt: string
  /** When the follow was last updated (ISO 8601). */
  updatedAt: string
}

PaginatedResult

A paginated result set.

interface PaginatedResult<T> {
  /** The result items for the current page. */
  data: T[]
  /** Total number of matching items across all pages. */
  total: number
  /** Maximum number of results per page. */
  limit: number
  /** Number of results skipped. */
  offset: number
}

PaginationOptions

Options for paginated queries.

interface PaginationOptions {
  /** Maximum number of results to return. */
  limit?: number
  /** Number of results to skip. */
  offset?: number
}

Functions

checkFollowing(req, res)

Checks if the current user is following a target.

function checkFollowing(req: MoleculeRequest, res: MoleculeResponse): Promise<void>

• req — The request with targetType and targetId params.
• res — The response object.

create(req, res)

Creates a follow relationship. Idempotent.

function create(req: MoleculeRequest, res: MoleculeResponse): Promise<void>

• req — The request with targetType and targetId params.
• res — The response object.

del(req, res)

Removes a follow relationship.

function del(req: MoleculeRequest, res: MoleculeResponse): Promise<void>

• req — The request with targetType and targetId params.
• res — The response object.

follow(followerId, targetType, targetId)

Creates a follow relationship. Idempotent — returns existing follow if already following.

function follow(followerId: string, targetType: string, targetId: string): Promise<Follow>

• followerId — The ID of the follower.
• targetType — The type of target being followed.
• targetId — The ID of the target being followed.

Returns: The created or existing follow.

following(req, res)

Lists targets the current user is following.

function following(req: MoleculeRequest, res: MoleculeResponse): Promise<void>

• req — The request with pagination query params.
• res — The response object.

getFollowerCount(targetType, targetId)

Gets the follower count for a target.

function getFollowerCount(targetType: string, targetId: string): Promise<number>

• targetType — The type of target.
• targetId — The ID of the target.

Returns: The number of followers.

getFollowers(targetType, targetId, options)

Gets paginated followers of a target.

function getFollowers(
  targetType: string,
  targetId: string,
  options?: PaginationOptions,
): Promise<PaginatedResult<Follow>>

• targetType — The type of target.
• targetId — The ID of the target.
• options — Pagination options.

Returns: Paginated followers.

getFollowing(userId, options)

Gets paginated targets a user is following.

function getFollowing(userId: string, options?: PaginationOptions): Promise<PaginatedResult<Follow>>

• userId — The follower's user ID.
• options — Pagination options.

Returns: Paginated follows.

getFollowingCount(userId)

Gets the following count for a user.

function getFollowingCount(userId: string): Promise<number>

• userId — The user ID.

Returns: The number of targets the user is following.

isFollowing(followerId, targetType, targetId)

Checks if a user is following a target.

function isFollowing(followerId: string, targetType: string, targetId: string): Promise<boolean>

• followerId — The follower's user ID.
• targetType — The type of target.
• targetId — The ID of the target.

Returns: true if following.

list(req, res)

Lists paginated followers of a target.

function list(req: MoleculeRequest, res: MoleculeResponse): Promise<void>

• req — The request with targetType and targetId params.
• res — The response object.

unfollow(followerId, targetType, targetId)

Removes a follow relationship.

function unfollow(followerId: string, targetType: string, targetId: string): Promise<void>

• followerId — The ID of the follower.
• targetType — The type of target.
• targetId — The ID of the target.

Constants

requestHandlerMap

Handler map for follow routes.

const requestHandlerMap: {
  readonly create: typeof create
  readonly del: typeof del
  readonly list: typeof list
  readonly following: typeof following
  readonly checkFollowing: typeof checkFollowing
}

routes

Routes for follow/unfollow, followers, following, and status check.

const routes: readonly [
  {
    readonly method: 'post'
    readonly path: '/follow/:targetType/:targetId'
    readonly handler: 'create'
    readonly middlewares: readonly ['authenticate']
  },
  {
    readonly method: 'delete'
    readonly path: '/follow/:targetType/:targetId'
    readonly handler: 'del'
    readonly middlewares: readonly ['authenticate']
  },
  {
    readonly method: 'get'
    readonly path: '/:targetType/:targetId/followers'
    readonly handler: 'list'
  },
  {
    readonly method: 'get'
    readonly path: '/following'
    readonly handler: 'following'
    readonly middlewares: readonly ['authenticate']
  },
  {
    readonly method: 'get'
    readonly path: '/follow/check/:targetType/:targetId'
    readonly handler: 'checkFollowing'
    readonly middlewares: readonly ['authenticate']
  },
]

Injection Notes

Requirements

Peer dependencies:

• @molecule/api-database ^1.0.1
• @molecule/api-i18n ^1.0.1
• @molecule/api-logger ^1.0.1
• @molecule/api-resource ^1.0.1

Runtime Dependencies

• @molecule/api-database

• @molecule/api-i18n

• @molecule/api-logger

• @molecule/api-resource

• List endpoints return a PAGINATED envelope { data, total, limit, offset }, not a bare array — read the rows off result.data (server). On the client, unwrapList(res) from @molecule/app-http normalizes this envelope (pass it the whole HttpResponse), so the rows come back; reading the response as a bare array — or res.data alone (which is the envelope) — yields an EMPTY list. Table: src/__setup__/follows.sql creates the single follows table. An mlcl-scaffolded API replays __setup__/*.sql automatically on migrate; anywhere else run it once — nothing at runtime creates it.

The follower is ALWAYS the authenticated user: handlers read res.locals.session (populated by your global auth middleware) and 401 without it — never accept a follower userId from the body or params. GET /:targetType/:targetId/followers is deliberately PUBLIC; gate it yourself if follower lists are private in your app.

targetType is a free-form string (user, post, …) — the package does not validate it against your schema, so constrain accepted values in your app if arbitrary types would be a problem.

E2E Tests

Integration checklist — drive the real UI (live preview, no mocks), adapt each item to this app's actual screens/flows, and check every box off one by one. A box you can't check is an integration bug to fix — not a skip:

• User A follows user B (POST /follow/user/:B): B's follower count and A's following count each increment by exactly one, B appears in A's following list (GET /following) and A appears in B's followers list (GET /user/:B/followers). Reload — the edge and both counts persist (it's a real follows row, not local UI state).
• Following is IDEMPOTENT: A following B a second time (double-tap Follow or replay the POST) creates NO duplicate edge and does NOT double-count — exactly one follows row exists for (A → B) and both counts are unchanged.
• Unfollow (DELETE /follow/user/:B) removes the edge: A's following count and B's follower count each decrement back, B leaves A's following list, A leaves B's followers, and GET /follow/check/user/:B now returns { following: false }.
• You cannot follow yourself: the UI never offers Follow on your own profile, and following your own id never inflates your own counts. This package's follow() does not reject followerId === targetId, so the app must guard it — verify the guard exists, don't assume it.
• AUTHORIZATION — the follower is ALWAYS the session user: handlers read res.locals.session and 401 without it, so no UI or endpoint lets you follow/unfollow on behalf of another user by passing their id, and follow/unfollow act only on your own edges. Signed in as A you can never make B follow or unfollow anyone.