Yup-schema-faker

yup	yup-schema-faker
~0.28.x	~2.28.x
~0.29.x	~2.29.x

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

Playground

Showcase

Getting Started

Setup

Install this package and peer dependencies.

yarn add --dev yup-schema-faker faker randexp

Usage

import * as yup from 'yup'
import { fake } from 'yup-schema-faker'

// write a schema
const schema = yup
  .object()
  .required()
  .noUnknown()
  .shape({
    name: yup.string().required().min(4).max(20),
    age: yup.number().required().min(18).max(100).positive().integer(),
    email: yup.string().email(),
    website: yup.string().url(),
    createdOn: yup.date().default(function () {
      return new Date()
    }),
  })

// generate a fake data
const fakeData = fake(schema)

console.log(fakeData)
/*
  {
    name: ' Assumenda eos volup',
    age: 53,
    email: 'Tatyana75@hotmail.com',
    website: 'https://ike.info',
    createdOn: '2003-12-22T20:52:08.501Z'
  }
*/

API

fake

Pass a yup schema and return a fake data.

Function signature:

interface Options {
  // see: https://github.com/jquense/yup#mixedwhenkeys-string--arraystring-builder-object--value-schema-schema-schema
  context?: object
  // see: https://github.com/jquense/yup#mixedvalidatevalue-any-options-object-promiseany-validationerror
  strict?: boolean
}

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

Example:

See usage

Extending Faker

Fake extended methods

Similar to yup.addMethod, yup-schema-faker provides a fakeDedicatedTest method to fake extending method for a schema.

Function signature:

function fakeDedicatedTest<Schema extends AnySchema>(
  schemaConstructor: (...arg: any[]) => Schema,
  name: string,
  fakeFn: (currentSchema: Schema) => any,
)

For Example:

See string.json example

Fake extended schemas

yup-schema-faker also provides a addFaker method, which gives you the ability to extend faker for custom schema or overide existing one.

Function signature:

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

For example:

See customMixed example

Setting a randomness 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 firstRandom = fake(string())

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

console.log(firstRandom === secondRandom) // true

TypeScript support

Step 1. Augment the yup module

import { AnySchema } from 'yup'
import { Fake } from 'yup-schema-faker'

declare module 'yup' {
  interface BaseSchema {
    fake<Schema extends AnySchema>(this: Schema): ReturnType<Fake<Schema>>
  }
}

Step 2. Add the method

import { addMethod, mixed } from 'yup'
import { fake } from 'yup-schema-faker'

addMethod(mixed, 'fake', function () {
  return fake(this)
})

Step 3. Use it!

import { boolean } from 'yup'

const booleanSchema = boolean().required()
const data = booleanSchema.fake() // boolean

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
  • ✅ 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
• date
  • ✅ date.min(limit: Date | string | Ref, message?: string | function): Schema
  • ✅ date.max(limit: Date | string | Ref, message?: string | function): Schema
• array
  • ✅ array.required(message?: string | function): Schema
  • ✅ array.of(type: Schema): 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)