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# promise-faker

Provides `Promise`-like APIs but runs synchronously. This module is useful for controlling flows.

## Install

```sh
$ npm install promise-faker
```

## Usage

```js
import FakePromise from 'promise-faker'

// Write flows as normal Promise does
function factory (p) {
  const result = p.resolve(1)
  .then(() => {
    return 2
  })

  // Not to make the following chain.
  return p.resolve(result, true)
}

// Then, run them as synchronous flows
factory(FakePromise)  // 2
factory(Promise)      // Promise {2}
```

FakePromise actually runs synchronously:

```js
Promise.resolve(1).then(console.log)
console.log(2)
// 2
// 1

FakePromise.resolve(3).then(console.log)
console.log(4)
// 3
// 4
```

## new FakePromise(executor)

- **executor** `Function(resolve, reject)`

Returns a fake promise

### FakePromise.resolve(subject [, end])

- **end** `?boolean=false` The additional parameter only for `FakePromise`, and if this parameter is `true`, it will try to get the final value or throw an error if there is a rejection.

```js
FakePromise.resolve(FakePromise.resolve(1), true)
// 1

FakePromise.resolve(FakePromise.reject('2'), true)
// -> throw '2'
```

And if the fake promise is still pending, an `Error('pending unexpectedly')` error will thrown.

```js
const p = new FakePromise((resolve, reject) => {
  return 1
})

try {
  FakePromise.resolve(p, true)
} catch (e) {
  console.log(e.message)  // 'pending unexpectedly'
}
```

### FakePromise.reject(subject)

Similar as `Promise.reject`, but returns a fake promise

### FakePromise.all(tasks)

Similar as `Promise.all`, but returns a fake promise

### promise.then(onResolve [, onReject])

Similar as `promise.then`, but returns a fake promise

### promise.catch(onReject)

Similar as `promise.catch`, but returns a fake promise

## await

The `FakePromise` instance could even be `await`ed

```js
console.log(await FakePromise.resolve(1))  // 1

await FakePromise.reject('error') // throw 'error'
```

## License

MIT