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const personGen = gen.object({
  name: gen.string,
  age: gen.int,
  orders: gen.array(gen.object({
    trackingId: gen.int,
    name: gen.string
  })),
  // ...
});

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{ result: false,
  'failing-size': 2,
  'num-tests': 3,
  fail: [ 2, -1 ],
  shrunk:
   { 'total-nodes-visited': 2,
     depth: 1,
     result: false,
     smallest: [ 0, -1 ] } }

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var testcheck = require('testcheck');
var gen = testcheck.gen;

testcheck.check(testcheck.property(
  [gen.int, gen.int], // generate two random integers
  function (a, b) {
    // check that the sum of the integers is always greater than any one number
    return a + b >= a && a + b >= b;
  }
));

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import {sampleOne} from 'babel-plugin-transform-flow-to-gen/api';

type Person = {
  name: string,
  age: number,
  setName: (name: string) => Person
};

const person = sampleOne(Person());

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import type {Person} from './types';

export default function setName(person: Person, name: string): Person {
  return {
    ...person,
    name
  };
}

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import setName from './setName';

import {types} from 'babel-plugin-transform-flow-to-gen/api';
import type {Person} from './types';

require('jasmine-check').install();

describe('setName', () => {
  it.check('sets a new name', [Person(), types.string()], (person, newName) => {
    const next = setName(person, newName);

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import uuid from 'uuid-v4';
import {sample} from 'babel-plugin-transform-flow-to-gen/api';
import type {$Gen} from 'babel-plugin-transform-flow-to-gen/Gen';

// FYI,
// type $Gen<T, _U> = T;

type User = {
  id: $Gen<string, uuid>, // $Gen only supports references to function calls
  name: string

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import {sampleOne} from 'babel-plugin-transform-flow-to-gen/api';

type Person = {
  name: string,
  age: number
}

function setName(person: Person, name: string): Person {
  return {
    ...person,

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import {sampleOne, types} from 'babel-plugin-transform-flow-to-gen/api';

const personGen =
  types.plainObject({
    name: types.string(),
    age: types.number()
  });

console.log(sampleOne(personGen));
// { "name": "rJJ9", "age": -1 }

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import {sample, sampleOne, types} from 'babel-plugin-transform-flow-to-gen/api';
import type {Animal, Dog} from './types';

const dogGen = Animal(types.literal('dog'));
const anySpeciesGen = Animal(types.string());

const dog = sampleOne(dogGen);

console.log(dog);
// { "species": "dog", "name": "ahKL9p" }