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# promise-loading-spinner

> Advanced handling of loaders/spinners based on one or multiple Promises.

## Why?

- **Show a spinner using a promise** Spinner will disappear when promise is resolved
- **No Spinner for short operations** Spinner won't show up for short operations so operation doesn't feel lazy
- **Support of multiple promises** Spinner will disappear when the last unresolved promise is resolved
- **Operations in a sequence** If there are multiple operations in a sequence the spinner will disappear when the last operation is finished

See this [Codepen](https://codepen.io/jenssimon/pen/NJmmJe).

## Install

```sh
$ yarn add promise-loading-spinner
```

## Usage

This shows loading spinners based on promises.

```javascript
import PromiseLoadingSpinner from 'promise-loading-spinner'

const loader = new PromiseLoadingSpinner({
  // options
})

// ...

const myPromise = new Promise((resolve) => {
  setTimeout(() => {
    resolve('done')
  }, 5000)
})

loader.loader(myPromise)
```

You can also use a wrapper function for a function that returns a promise or uses `await`:

```javascript
const myFunction = loader.wrapFunction(async (url) => {
  const response = await fetch(url)
  const result = await response.json()
  return result
})

myFunction(someUrl)
```

It also exports a method decorator:

```javascript
const loaderDecorator = loader.decorator.bind(loader)

class MyClass {
  @loaderDecorator()
  async foo() {
    // ...
  }
}
```

All ways to add a promise can also take a configuration object as an optional parameter.

Option  | Description | Type
--------|-------------|------
`skipDelays` |  Skip all delays (`initDelay`, `delay`) | `boolean`

Examples:

```javascript

// loader
loader(promise, { skipDelays: true })

// wrapFunction:
wrapFunction(fnc, { skipDelays: true })

// decorator:
class MyClass {
  @loaderDecorator({ skipDelays: true })
  async foo() {
    // ...
  }
}
```

## Options

Option  | Description | Type | Default
--------|-------------|------|--------
`delay` | Time (ms) until spinner will show up to handle short operations without a spinner | `Number` | `300`
`closeDelay` | Time (ms) to wait until last promise is resolved to enable multiple operations in a sequence without a "flickering" spinner | `Number` | `10`
`initDelay` | Delay (ms) after loader initialization to suppress spinners on page load | `Number` | `1000`
`loaderElement` | the element which represents the spinner | `string` (selector) or `HTMLElement`| `js-page-loader`
`classActive` | class name used to show the spinner | `string` | `is-active`

## License

MIT © 2023 [Jens Simon](https://github.com/jenssimon)

[npm-url]: https://www.npmjs.com/package/promise-loading-spinner
[npm-image]: https://badgen.net/npm/v/promise-loading-spinner
[npm-downloads-image]: https://badgen.net/npm/dw/promise-loading-spinner

[gh-url]: https://github.com/jenssimon/promise-loading-spinner
[gh-stars-image]: https://badgen.net/github/stars/jenssimon/promise-loading-spinner
[gh-forks-image]: https://badgen.net/github/forks/jenssimon/promise-loading-spinner
[gh-status-image]: https://github.com/jenssimon/promise-loading-spinner/actions/workflows/ci.yml/badge.svg
[gh-status-url]: https://github.com/jenssimon/promise-loading-spinner/actions/workflows/ci.yml

[coveralls-url]: https://coveralls.io/github/jenssimon/promise-loading-spinner?branch=main
[coveralls-image]: https://coveralls.io/repos/github/jenssimon/promise-loading-spinner/badge.svg?branch=main