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ts-transform-json-schema

library2.0.3jsnpmunverified

ts-transform-json-schema (v2.0.3) is a TypeScript custom transformer that generates inline JSON Schema from TypeScript interfaces and types at compile time. It replaces type annotations with actual schema objects, eliminating the need for runtime reflection. The library integrates with TTypeScript and supports schema options like additionalProperties. It is maintained sparsely, with the latest version from February 2021. Key differentiators: compile-time transformation vs runtime generators, zero runtime cost, and direct TypeScript type source of truth.

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npm install ts-transform-json-schema

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INSTALL

IMPORT

SIG · TS-TRANSFORM-JSON-

ts-transform-json-schema

devopsjavascriptv2.0.3

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

fromType

✓ import { fromType } from 'ts-transform-json-schema'

✗ import JsonSchema from 'ts-transform-json-schema' // Non-named import doesn't work for fromType

fromType is a named export. Default export is not available.

JsonSchema (namespace)

✓ import * as JsonSchema from 'ts-transform-json-schema'

✗ const JsonSchema = require('ts-transform-json-schema') // CommonJS require not supported in transformers

Namespace import for use with JsonSchema.fromType() pattern.

types only (TS interface)

✓ import type { SomeInterface } from './types'

✗ import { SomeInterface } from './types' // Can cause runtime import if not using type-only

Interfaces used only in generics should be imported with type-only imports to avoid runtime overhead.

Configures TTypeScript and demonstrates compile-time JSON Schema generation from a TypeScript interface.

// tsconfig.json { "compilerOptions": { "target": "es2015", "module": "commonjs", "plugins": [ { "transform": "ts-transform-json-schema", "type": "program" } ] }, "include": ["src"] } // src/index.ts import { fromType } from 'ts-transform-json-schema'; interface User { id: number; name: string; email?: string; } export const userSchema = fromType<User>({ additionalProperties: false }); // Compiled output (after ttsc): // const userSchema = { // type: 'object', // properties: { // id: { type: 'number' }, // name: { type: 'string' }, // email: { type: 'string' } // }, // required: ['id', 'name'], // additionalProperties: false, // $schema: 'http://json-schema.org/draft-07/schema#' // };

Debug

Known issues

gotchaRequires TTypeScript: ts-transform-json-schema is a TypeScript custom transformer and cannot be used with standard tsc.

fix

Install and use ttypescript: npm install ttypescript --save-dev and run ttsc instead of tsc.

affects: >=0.0.0

gotchaUnsupported types: Complex types like union types, intersection types, generics, and mapped types may not be fully supported or produce incorrect schema.

fix

Stick to simple interfaces and type aliases. Test generated schema for complex types.

affects: >=0.0.0

breakingBreaking change in v2: The fromType signature changed; options object now accepts additionalProperties etc. directly.

fix

Update calls from fromType<SomeInterface>(false) to fromType<SomeInterface>({ additionalProperties: false })

affects: >=2.0.0

deprecatedDraft 07 only: The generated schema uses JSON Schema draft-07. Draft 2020-12 is not supported.

fix

No fix; library does not support other drafts. Consider alternatives if newer draft required.

affects: >=0.0.0

Errors

Common errors & fixes

error TS2339: Property 'fromType' does not exist on type 'typeof import("ts-transform-json-schema")'

Using namespace import without enabling the transformer in tsconfig.json.

fix

Add ts-transform-json-schema to compilerOptions.plugins in tsconfig.json and use ttsc.

TypeError: (0 , ts_transform_json_schema_1.fromType) is not a function

Running with tsc instead of ttsc. The transformer is not applied.

fix

Use ttsc command from ttypescript package: npx ttsc

Cannot find module 'ts-transform-json-schema'

Package not installed, or using ts-node without tsconfig-paths.

fix

Run npm install ts-transform-json-schema --save-dev and ensure tsconfig.json has the plugin entry.

Upgrade

Version history

2.0.3latest on npm

Audit

Dependencies

ttypescriptrequiredRequired to run TypeScript custom transformers

Agent activity

6 hits · last 30 days

node

Resources

githubssh://git@github.com/marionebl/ts-transform-json-schema ↗

packagets-transform-json-schema ↗

homepagehttps://github.com/marionebl/ts-transform-json-schema#readme ↗