promisify-file-reader/readme.md

Promise File Reader

# Promisify File Reader

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## Usage

```html
<script src="https://unpkg.com/promisify-file-reader"></script>
```

```html
<script type="module">
  import PromisifyFileReader from 'https://unpkg.com/promisify-file-reader?module'
</script>
```

## Files

```text
dist/
├─ index.cjs        ( CommonJS )
├─ index.js         ( UMD )
├─ index.min.js     ( UMD, compressed )
├─ index.mjs        ( ES Module )
└─ index.min.mjs    ( ES Module, compressed )
```

## API

### Prototype

supported all `FileReader` methods:

- `readAsArrayBuffer`
- `readAsBinaryString`
- `readAsDataURL`
- `readAsText`

> `FileReader#readAsBinaryString` is not available in some browser, like IE 10
>
> we use arrayBuffer to binaryString to support this method

example:

```js
const fileReader = new PromisifyFileReader()
const result = await fileReader.readAsArrayBuffer(file)
```

### Static methods

in fact `new PromisifyFileReader()` is not really required, all methods can use as static

- `readAsArrayBuffer`
- `readAsBinaryString`
- `readAsDataURL`
- `readAsText`

example:

```js
const result = await PromisifyFileReader.readAsArrayBuffer(file)
```

### Shortcuts

you can also strip the `readAs` prefix

- `arrayBuffer`
- `binaryString`
- `dataURL`
- `text`

Notice: shortcuts are **NOT** available in prototype

example:

```js
const result = await PromisifyFileReader.arrayBuffer(file)
// => same as readAsArrayBuffer
```

## ES Module

the ES Module build exports

```js
{
  // default
  PromisifyFileReader as default,

  // named
  arrayBuffer,
  binaryString,
  dataURL,
  text,
  readAsArrayBuffer,
  readAsBinaryString,
  readAsDataURL,
  readAsText,
}
```

import example:

```js
// import default
import PromisifyFileReader from 'promisify-file-reader'

// import named
import {
  arrayBuffer,
  // ...
} from 'promisify-file-reader'

// import both
import PromisifyFileReader, {
  arrayBuffer,
  // ...
} from 'promisify-file-reader'
```

## Related

- [promisify-file](https://github.com/fisker/promisify-file)