Registry / testing / json-schema-faker

json-schema-faker

library0.6.2jsnpmunverified

Generate valid JSON mock data from JSON Schema definitions. v0.6.2 supports JSON Schema 2019-09 and 2020-12 with deterministic output via seeded PRNG (Mulberry32). Zero production dependencies. Key differentiators: built-in format generators (email, uuid, etc.), extension support for faker/chance, custom keywords via define(), and sequential auto-incrementing seeds via createGenerator().

testing

npm install json-schema-faker

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · JSON-SCHEMA-FAKER

json-schema-faker

testingjavascriptv0.6.2

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.

generate

✓ import { generate } from 'json-schema-faker'

✗ const generate = require('json-schema-faker').generate

ESM-only since v0.6.0; CommonJS require works but is discouraged. The function returns a Promise.

createGenerator

✓ import { createGenerator } from 'json-schema-faker'

✗ import { createGenerator } from 'json-schema-faker/cjs'

Named export, not default. No subpath exports.

registerFormat

✓ import { registerFormat } from 'json-schema-faker'

✗ import registerFormat from 'json-schema-faker'

Named export, not default.

define

✓ import { define } from 'json-schema-faker'

Used for custom keyword extensions. The callback receives (value, schema, ctx).

createRemoteResolver

✓ import { createRemoteResolver } from 'json-schema-faker'

✗ import { createRemoteResolver } from 'json-schema-faker/remote'

No subpath exports; all are top-level.

Generate a mock object with string, integer, email, and array properties from a JSON Schema.

import { generate } from 'json-schema-faker'; const schema = { type: 'object', properties: { name: { type: 'string', minLength: 2 }, age: { type: 'integer', minimum: 0, maximum: 120 }, email: { type: 'string', format: 'email' }, tags: { type: 'array', items: { type: 'string' }, maxItems: 3 } }, required: ['name', 'email'] }; const data = await generate(schema); console.log(data); // Example: { name: 'John', age: 50, email: 'john.doe@example.com', tags: ['tag1', 'tag2'] }

Debug

Known issues

breakingRequires ESM imports starting from v0.6.0

fix

Use import syntax instead of require(). If using CommonJS, use dynamic import: const { generate } = await import('json-schema-faker');

affects: >=0.6.0

gotchagenerate() returns a Promise, not a synchronous value. Many users forget to await.

fix

Always await: const data = await generate(schema);

affects: >=0.5.0

gotchaSeeded generation may change between minor versions; do not rely on exact output for tests across versions.

fix

Pin exact version and regenerate snapshots on upgrades.

affects: *

deprecatedCustom registerFormat for standard formats (email, uuid) is redundant; they are built-in since v0.5.0.

fix

Use built-in formats directly; registerFormat is only needed for custom formats not in the standard list.

affects: >=0.5.0

gotchaWhen using createGenerator(), successive calls use auto-incrementing seeds; do not re-seed within the same generator instance.

fix

If you need the same output repeatedly, create a new generator with the same seed each time.

affects: >=0.6.0

Errors

Common errors & fixes

TypeError: generate is not a function

Using default import instead of named import.

fix

Use import { generate } from 'json-schema-faker'

Error: generate(...) returned a Promise, not a value

Missing await before generate() call.

fix

Add await: const data = await generate(schema);

SyntaxError: Cannot use import statement outside a module

Using ESM import in a CommonJS script without type:module.

fix

Add type:module to package.json or use dynamic import: const { generate } = await import('json-schema-faker');

Error: Cannot find module 'json-schema-faker'

Package not installed.

fix

Run npm install json-schema-faker

Upgrade

Version history

0.6.2latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

8 hits · last 30 days

node

Resources

githubhttps://github.com/json-schema-faker/json-schema-faker ↗

packagejson-schema-faker ↗

homepagehttps://json-schema-faker.js.org/ ↗