Yup-schema-faker

Yup-schema-faker will generate you a fake data based on your yup schema.

Showcase & Playground

Key features:

• Extensible: you can fake for your own schemas, methods or override existing ones.

Version Compatibiility

yup	@types/yup	yup-schema-faker
~0.28.x	~0.28.x	~2.28.x
~0.29.x	~0.29.x	~2.29.x
>= 0.32.0, <= 0.32.10	N/A	~2.32.x
>= 0.32.11	N/A	main

Getting Started

Install yup-schema-faker and its peer dependencies with your favorite package manager:

pnpm add yup@^0.32.11
pnpm add -D yup-schema-faker@^5.0.0
pnpm add -D @faker-js/faker@^7.4.0
pnpm add -D randexp@^0.5.3

Usage:

import { object, string, number, date } from 'yup'
import { install, fake } from 'yup-schema-faker'
import { faker } from '@faker-js/faker'
// import { faker } from '@faker-js/faker/locale/ja'

// Before using it, you need to install all built-in fakers:
install(faker)

// If you have extended fakers, you need to install them here, too:
//
// addFaker(boolean, BooleanFaker)
//
// fakeDedicatedTest(boolean, 'is-value', schema => {
//   const isValueTest = schema.tests.find(test => test.OPTIONS.name === 'is-value')!
//   return isValueTest.OPTIONS.params?.value === 'true'
// })

// Define schema:
const userSchema = object({
  name: string().required(),
  age: number().required().positive().integer(),
  email: string().email(),
  website: string().url().nullable(),
  createdOn: date().default(() => new Date()),
}).noUnknown()

// Fake data:
const fakeUser = fake(userSchema)
// {
//   "name": " Assumenda eos volup",
//   "age": 73684592,
//   "email": "[e-mail]",
//   "website": "https://well-worn-co-producer.org",
//   "createdOn": "Fri Jun 09 2006 19:49:16 GMT+0800 (台北標準時間)",
// }

API

fake

Pass a yup schema and return a fake data.

Function signature:

interface Options {
  // please see https://github.com/jquense/yup#schemastrictenabled-boolean--false-schema
  strict?: boolean

  // External values that used to resolve conditions and references.
  // please see https://github.com/jquense/yup#schemacastvalue-any-options---infertypeschema
  context?: object
}

function fake<Schema etends AnySchema>(schema: Schema, options?: Options): ReturnType<Schema['cast']>;

Example:

const schema1 = yup.number().required()
fake(schema1)
// 763 or "971235"
fake(schema1, { strict: true })
// 9102

const schema2 = object({
  baz: ref('foo.bar'),
  foo: object({
    bar: string(),
  }),
  x: ref('$x'),
})
const context = { x: 5 }
fake(schema2, { context })
// {
//   foo: {
//     bar: 'Sit atque temporibus',
//   },
//   baz: 'Sit atque temporibus',
//   x: 5,
// }

fakeDedicatedTest

Similar to addMethod, you can use fakeDedicatedTest to fake extended methods.

Function signature:

function fakeDedicatedTest<SchemaConstructor extends (...args: any[]) => AnySchema>(
  schemaConstructor: SchemaConstructor,
  name: string,
  fakeFn: (schema: ReturnType<SchemaConstructor>) => ReturnType<ReturnType<SchemaConstructor>['cast']>,
)

Example: string.json example

addFaker

You can create new schemas in yup. Similarly, you can use addFaker to create corresponding fakers for these schemas.

Function signature:

function addFaker<Schema extends AnySchema, Faker>(
  schemaConstructor: (...arg: any[]) => Schema,
  fakerConstructor: Faker,
)

Example: customMixed example

seed

If you want to produce consistent results, you can set your own seed with integer:

import { seed, fake } from 'yup-schema-faker'
import { string } from 'yup'

seed(123)
const first = fake(string())

seed(123)
const second = fake(string())

console.log(first === second) // true

Supported yup API

• yup
  • ✅ yup.ref(path: string, options: { contextPrefix: string }): Ref
  • ✅ yup.lazy((value: any) => Schema): Lazy
• mixed
  • ✅ mixed.strict(isStrict: boolean = false): Schema
  • ✅ mixed.default(value: any): Schema
  • ✅ mixed.nullable(isNullable: boolean = true): Schema
  • ✅ mixed.required(message?: string | function): Schema
  • ✅ mixed.notRequired(): Schema Alias: optional()
  • ✅ mixed.defined(): Schema
  • ✅ mixed.oneOf(arrayOfValues: Array, message?: string | function): Schema Alias: equals
  • ✅ mixed.notOneOf(arrayOfValues: Array, message?: string | function)
  • ✅ mixed.when(keys: string | Array, builder: object | (value, schema)=> Schema): Schema
• string
  • ✅ string.required(message?: string | function): Schema
  • ✅ string.length(limit: number | Ref, message?: string | function): Schema
  • ✅ string.min(limit: number | Ref, message?: string | function): Schema
  • ✅ string.max(limit: number | Ref, message?: string | function): Schema
  • ✅ string.matches(regex: Regex, message?: string | function): Schema
  • ❌ string.matches(regex: Regex, options: { message: string, excludeEmptyString: bool }): Schema

    this feature cannot be detected, use another schema to achieve this behavior

  • ✅ string.email(message?: string | function): Schema
  • ✅ string.url(message?: string | function): Schema
  • ✅ string.uuid(message?: string | function): Schema
  • ✅ string.trim(message?: string | function): Schema

    generate trimmed string iff in strict mode

  • ✅ string.lowercase(message?: string | function): Schema

    generate lowercase string iff in strict mode

  • ✅ string.uppercase(message?: string | function): Schema

    generate uppercase string iff in strict mode

• number
  • ✅ number.min(limit: number | Ref, message?: string | function): Schema
  • ✅ number.max(limit: number | Ref, message?: string | function): Schema
  • ✅ number.lessThan(max: number | Ref, message?: string | function): Schema
  • ✅ number.moreThan(min: number | Ref, message?: string | function): Schema
  • ✅ number.positive(message?: string | function): Schema
  • ✅ number.negative(message?: string | function): Schema
  • ✅ number.integer(message?: string | function): Schema
• boolean
  • ✅ boolean.isTrue(message?: string | function): Schema
  • ✅ boolean.isFalse(message?: string | function): Schema
• date
  • ✅ date.min(limit: Date | string | Ref, message?: string | function): Schema
  • ✅ date.max(limit: Date | string | Ref, message?: string | function): Schema
• array
  • ✅ array.of(type: Schema): Schema
  • ✅ array.length(length: number | Ref, message?: string | function): Schema
  • ✅ array.min(limit: number | Ref, message?: string | function): Schema
  • ✅ array.max(limit: number | Ref, message?: string | function): Schema
• object
  • ✅ object.shape(fields: object, noSortEdges?: Array<[string, string]>): Schema
  • ✅ object.noUnknown(onlyKnownKeys: boolean = true, message?: string | function): Schema

Contributing

We love your input! We want to make contributing to this project as easy and transparent as possible, whether it's:

• Reporting a bug
• Discussing the current state of the code
• Submitting a fix
• Proposing new features
• Becoming a maintainer

People love thorough bug reports. I'm not even kidding.

Report bugs using Github's issues

We use GitHub issues to track public bugs. Report a bug by opening a new issue; it's that easy!

Write bug reports with detail, background, and sample code

Great Bug Reports tend to have:

• A quick summary and/or background
• Steps to reproduce
  • Be specific!
  • Give sample code if you can.
• What you expected would happen
• What actually happens
• Notes (possibly including why you think this might be happening, or stuff you tried that didn't work)

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