@mostajs/orm-adapter

Bidirectional schema conversion between @mostajs/orm EntitySchema[] and Prisma / JSON Schema / OpenAPI / Native TS.

Every adapter works both directions since v0.6.0 — import your legacy schema, or export EntitySchemas as Prisma / OpenAPI / JSON Schema for downstream tooling (Swagger UI, Ajv, Prisma CLI, …).

Adapters

Adapter	Input format	toEntitySchema	fromEntitySchema
Native	EntitySchema[] object / JSON	✅ passthrough + validation	✅ passthrough
Prisma	.prisma file (string)	✅ full	✅ emits .prisma
JSON Schema	Draft 2020-12 / 2019-09 / Draft-07	✅ full	✅ emits 2020-12
OpenAPI	3.1 / 3.0 / Swagger 2.0 (JSON or YAML)	✅ full	✅ emits OpenAPI 3.1

Validated on the FitZoneGym fixture (40 real models with enums, composite uniques, M:1, 1:N, N:N, self-relations).

Install

npm install @mostajs/orm-adapter @mostajs/orm

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Quick start

Auto-detection via Registry (recommended)

import { createDefaultRegistry } from '@mostajs/orm-adapter'
import { readFileSync } from 'fs'

const registry = createDefaultRegistry()   // registers native, prisma, jsonschema, openapi
const entities = await registry.fromAny(readFileSync('./schema.prisma', 'utf8'))
// → EntitySchema[]  — hand to @mostajs/orm's registerSchemas / initSchema

Subpath imports (pull only the parser you need)

import { PrismaAdapter }     from '@mostajs/orm-adapter/prisma'
import { JsonSchemaAdapter } from '@mostajs/orm-adapter/jsonschema'
import { OpenApiAdapter }    from '@mostajs/orm-adapter/openapi'
import { NativeAdapter }     from '@mostajs/orm-adapter/native'

Subpath imports avoid pulling parsers you're not using (@mrleebo/prisma-ast, ajv, @readme/openapi-parser, js-yaml).

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Forward conversions — toEntitySchema()

Prisma → EntitySchema[]

import { PrismaAdapter } from '@mostajs/orm-adapter/prisma'

const entities = await new PrismaAdapter().toEntitySchema(
  readFileSync('./schema.prisma', 'utf8'),
  { onWarning: w => console.warn(`[${w.code}] ${w.message}`) },
)

Handles every Prisma feature that maps cleanly : all scalars (String, Int, BigInt, Float, Decimal, Boolean, DateTime, Json, Bytes), modifiers (?, []), field attributes (@id, @unique, @default, @map, @updatedAt, @db.*), model attributes (@@id, @@unique, @@index, @@map, @@schema, @@fulltext), enums, relations (1:1, 1:N, M:N with implicit junction synthesis, self-relations via @relation("Name")), referential actions, default sentinels (AUTOINCREMENT, NOW, UUID_V4/V7, CUID/CUID2, NANOID, ULID, OBJECT_ID), and auto-detection of the createdAt + updatedAt convention.

JSON Schema → EntitySchema[]

import { JsonSchemaAdapter } from '@mostajs/orm-adapter/jsonschema'

const entities = await new JsonSchemaAdapter().toEntitySchema(jsonSchemaObject)

Supports every draft (2020-12 / 2019-09 / Draft-07), all formats (date-time, uuid, uri, email, …), nullable (OpenAPI 3.0 nullable: true and 3.1 type: [T, "null"]), allOf flattening (inheritance), oneOf discriminator, $ref resolution (internal + external), cycle detection. Honors x-mostajs-entity, x-mostajs-relation, x-primary, x-unique, x-index, x-indexes, x-autoIncrement.

OpenAPI → EntitySchema[]

import { OpenApiAdapter } from '@mostajs/orm-adapter/openapi'

// JSON object, JSON string, or YAML string — all accepted
const entities = await new OpenApiAdapter().toEntitySchema(openApiSpec)

• OpenAPI 3.1 : full JSON Schema 2020-12 semantics
• OpenAPI 3.0.x : auto-normalized to 3.1 shape (nullable: true → type: [T, "null"], example: X → examples: [X], etc.)
• Swagger 2.0 : detected, emits PREVIEW_FEATURE warning (no full support)
• YAML input parsed natively via js-yaml — no pre-parse needed

Native (passthrough + validation)

import { NativeAdapter } from '@mostajs/orm-adapter/native'

const validated = await new NativeAdapter().toEntitySchema(mySchemas)
// Accepts { name, collection, fields, ... } — runs structural validation,
// warns on missing required properties, returns the same array.

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Reverse conversions — fromEntitySchema() (since v0.6.0)

The reverse direction lets you export your EntitySchema[] to any supported format — for migrations out, for downstream tooling (Swagger UI, Ajv, Prisma CLI), or for cross-team handoff.

EntitySchema[] → Prisma

import { PrismaAdapter } from '@mostajs/orm-adapter/prisma'

const prismaSrc: string = await new PrismaAdapter().fromEntitySchema(entities)
// Complete .prisma string : generator + datasource + enums + models
await writeFile('./schema.prisma', prismaSrc)
// Then : npx prisma generate, npx prisma migrate dev, …

Emits a full Prisma schema (generator client + datasource db + enum blocks + model blocks). Mapping :

EntitySchema feature	Prisma emit
type: 'string' / 'text'	String
type: 'number'	Float
type: 'boolean' / 'date' / 'json'	Boolean / DateTime / Json
type: 'array', arrayOf: 'string'	String[] (optional modifier omitted — arrays already allow empty)
enum: [...] on a field	dedicated enum EntityField { ... } block
required: false	? modifier
unique: true	@unique
default: '__MOSTA_NOW__' / 'now'	@default(now())
default: '__MOSTA_OBJECT_ID__' / '__MOSTA_UUID__'	@default(uuid())
default: <scalar>	@default(X) — enum values unquoted, strings quoted
relation.type: 'many-to-one' / 'one-to-one' (owning)	fkId String? + rel X? @relation(fields: [fkId], references: [id])
relation.type: 'many-to-one' / 'one-to-one' (mappedBy / inverse)	rel X? (no @relation)
relation.type: 'one-to-many' / 'many-to-many'	rel X[]
relation.onDelete	, onDelete: Cascade / SetNull / Restrict / NoAction
indexes: [{ unique: true, fields: { a: 'asc', b: 'asc' } }]	@@unique([a, b])
indexes: [{ fields: { ... } }] (non-unique)	@@index([...])
collection: "members" (when ≠ default)	@@map("members")

Override the emitted datasource block via opts.extensions.datasource:

const out = await new PrismaAdapter().fromEntitySchema(entities, {
  extensions: {
    datasource: { provider: 'postgresql', url: 'env("DATABASE_URL")' },
  },
})

Round-trip : toEntitySchema(fromEntitySchema(entities)) parses back without error on the 40-entity FitZoneGym fixture. Field-level properties (type, required, unique, default sentinels) survive the round-trip. Caveats : @@index columns without sort order are emitted without direction ; exotic @map overrides can lose alias data.

EntitySchema[] → JSON Schema 2020-12

import { JsonSchemaAdapter } from '@mostajs/orm-adapter/jsonschema'

const doc: object = await new JsonSchemaAdapter().fromEntitySchema(entities)
// {
//   "$schema": "https://json-schema.org/draft/2020-12/schema",
//   "title":   "mostajs entities",
//   "definitions": {
//     "User":    { "$id": "User",    "type": "object", "properties": { ... }, "required": [...] },
//     "Profile": { "$id": "Profile", ... }
//   }
// }

Relations become $ref (for M:1 / 1:1) or { type: 'array', items: { $ref } } (for 1:N / N:N), annotated with an x-mostajs-relation extension that preserves the full RelationDef (type, joinColumn, mappedBy, onDelete, cascade, fetch, …) for lossless reverse conversion.

Extension fields emitted for round-trip fidelity :

• x-mostajs-collection — table/collection name
• x-mostajs-timestamps — boolean
• x-mostajs-unique (on a property) — field-level unique
• x-mostajs-indexes — full indexes array
• x-mostajs-relation (on a property) — full RelationDef

EntitySchema[] → OpenAPI 3.1

import { OpenApiAdapter } from '@mostajs/orm-adapter/openapi'

const spec: object = await new OpenApiAdapter().fromEntitySchema(entities)
// {
//   "openapi": "3.1.0",
//   "info":    { "title": "mostajs entities", "version": "1.0.0" },
//   "paths":   {},
//   "components": { "schemas": { "User": {...}, "Profile": {...} } }
// }
await writeFile('./openapi.json', JSON.stringify(spec, null, 2))

Produces a minimal but valid OpenAPI 3.1 document. paths is empty — the developer wires routes on top. The schema shapes in components.schemas are identical to the JSON Schema variant (same mapping, same x-mostajs-* extensions), so tools like Swagger UI, Redoc, Scalar, or Stoplight render the generated schemas out of the box.

EntitySchema[] → Native (passthrough)

import { NativeAdapter } from '@mostajs/orm-adapter/native'

const out = await new NativeAdapter().fromEntitySchema(entities)
// → Array<EntitySchema> — returns the same array, validated for structural shape

Useful when you want structural validation before handing the schemas off to @mostajs/orm.

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Via @mostajs/orm-cli (no code)

If you prefer the interactive CLI, @mostajs/orm-cli@0.4.6+ exposes the reverse adapters behind menu e) Export entities :

npx @mostajs/orm-cli@latest
# → menu e
#
#   1) Prisma        → prisma/schema.prisma
#   2) JSON Schema   → schema.json (2020-12)
#   3) OpenAPI 3.1   → openapi.json
#   4) Native (TS)   → src/schemas.ts

The CLI reads .mostajs/generated/entities.json (produced by menu 1 — Convert) and writes the chosen format to disk.

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API reference

IAdapter interface

interface IAdapter {
  readonly name: string
  readonly vendor: string
  readonly version: string
  canParse(input: string | object): boolean
  toEntitySchema(input: string | object, opts?: AdapterOptions): Promise<EntitySchema[]>
  fromEntitySchema?(entities: EntitySchema[], opts?: AdapterOptions): Promise<string | object>
}

AdapterOptions

Option	Type	Description
strict	boolean	Warnings become exceptions (fail-fast)
onWarning	(w: AdapterWarning) => void	Callback for each warning
extensions	Record<string, unknown>	Custom values (e.g. datasource override for Prisma reverse)
relationStrategy	'explicit' | 'auto' | 'none'	Relation detection mode (forward only)
unknownTypesFallback	'json' | 'error' | 'string'	Fallback for unmappable types (forward only)

Warning codes

• UNSUPPORTED_FEATURE — source has a feature the target cannot express
• LOSSY_CONVERSION — precision or constraint lost during mapping
• MISSING_METADATA — expected metadata absent
• AMBIGUOUS_MAPPING — multiple valid interpretations
• PREVIEW_FEATURE — experimental / preview feature used
• FALLBACK_APPLIED — default strategy applied
• CYCLIC_REFERENCE — self-referencing schema detected
• UNKNOWN_EXTENSION — unrecognized x-* extension

Registry

import { createDefaultRegistry, AdapterRegistry } from '@mostajs/orm-adapter'

const registry = createDefaultRegistry()
// or build your own :
const reg = new AdapterRegistry()
reg.register(new PrismaAdapter())
reg.register(new JsonSchemaAdapter())

// Auto-detect the right adapter
const entities = await reg.fromAny(input)

// Explicit selection
const entities2 = await reg.fromAny(input, { adapterName: 'prisma' })

Writing a custom adapter

import { AbstractAdapter, WarningCode, type AdapterOptions } from '@mostajs/orm-adapter'
import type { EntitySchema } from '@mostajs/orm'

export class MyCustomAdapter extends AbstractAdapter {
  readonly name    = 'my-format'
  readonly vendor  = 'my-org'
  readonly version = '0.1.0'

  canParse(input: string | object): boolean {
    return typeof input === 'string' && input.includes('@my-format')
  }

  async toEntitySchema(input: string | object, opts?: AdapterOptions): Promise<EntitySchema[]> {
    // Emit a warning that doesn't fail by default, but does fail with opts.strict:
    this.warn(opts, {
      code: WarningCode.LOSSY_CONVERSION,
      message: 'Some feature cannot be mapped exactly',
      entity: 'Foo',
    })
    return [/* ... EntitySchema[] */]
  }

  // Optional : reverse direction
  async fromEntitySchema(entities: EntitySchema[]): Promise<string> {
    return entities.map(e => `my-format ${e.name} { ... }`).join('\n')
  }
}

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Roadmap

• v0.1.0 – v0.5.1 ✅ Forward adapters for all 4 formats + 238 tests + YAML + real-world fixes (40-entity FitZoneGym schema)
• v0.6.0 ✅ Bidirectional — fromEntitySchema on all 4 adapters, integrated into @mostajs/orm-cli via menu e
• v0.7.0 — Round-trip strictness : toPrismaSchema(fromPrismaSchema(x)) ≡ x on the field-for-field level (stable @@map, @db.* preservation)
• v1.0.0 — Production-ready : plugin API, CLI mostajs export --to <format> subcommand, published type definitions for downstream tsup / rollup use

Ecosystem

• @mostajs/orm — the ORM backing all these schemas (13 databases)
• @mostajs/orm-bridge — keep your Prisma code, run on 13 databases (drop-in createPrismaLikeDb)
• @mostajs/orm-cli — interactive CLI (Convert / Apply / Seed / Export / Bootstrap)

License

AGPL-3.0-or-later + commercial license available.

For closed-source commercial use : drmdh@msn.com

Author

Dr Hamid MADANI drmdh@msn.com

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Part of the @mostajs ecosystem — 13 databases, 11 transports, one unified backend.