it-concat

Concat all buffers/strings yielded from an async iterable into a single BufferList/string

Install

$ npm i it-concat

Browser <script> tag

Loading this module through a script tag will make it's exports available as ItConcat in the global namespace.

<script src="https://unpkg.com/it-concat/dist/index.min.js"></script>

Usage

Concat Uint8Arrays to a single Uint8ArrayList:

import concat from 'it-concat'
import { toString } from 'uint8arrays'
import fs from 'fs'

fs.writeFileSync('./test.txt', 'Hello World!')

// Node.js Readable Streams are async iterables!
const chunks = await concat(fs.createReadStream('./test.txt'))

// chunks is a Uint8ArrayList
console.log(chunks)
/*
Uint8ArrayList {
  _bufs: [ <Uint8Array 48 65 6c 6c 6f 20 57 6f 72 6c 64 21> ],
  length: 12
}
*/
console.log(toString(chunks.subarray)))
// Hello World!

Concat Uint8Arrays to a single string:

import concat from 'it-concat'
import fs from 'fs'

fs.writeFileSync('./test.txt', 'Hello World!')

// Node.js Readable Streams are async iterables!
// Note that we pass `{ type: 'string' }` to tell concat that we want a string
// back and not a Uint8Array. This is necessary because the source data is Uint8Array(s).
const chunks = await concat(fs.createReadStream('./test.txt'), { type: 'string' })

console.log(chunks)
// Hello World!

Concat strings to a single string:

import concat from 'it-concat'
import fs from 'fs'

fs.writeFileSync('./test.txt', 'Hello World!')

// Node.js Readable Streams are async iterables!
// Note that we don't need to pass `{ type: 'string' }` to tell concat that we
// want a string back because the source data is Uint8Array(s).
const chunks = await concat(fs.createReadStream('./test.txt', { encoding: 'utf8' }))

console.log(chunks)
// Hello World!

API

import concat from 'it-concat'

concat(source, options?): Promise

Concat all Uint8Arrays or strings yielded from the async iterable source into a single Uint8ArrayList or string.

• source (AsyncIterable<Uint8Array | Uint8ArrayList | string>) - the source iterable to concat from
• options (Object) - optional options
• options.type (string) - return type of the function, pass 'string' to recieve a string or 'Uint8Array' for a Uint8ArrayList.

Returns a Promise that resolves to a Uint8ArrayList or string.

If options.type is not passed the type of the objects yielded from the source is detected and a Uint8ArrayList or string is returned appropriately. If the source does not yield anything an empty Uint8ArrayList is returned. If the source is expected to return strings (but may not yield anything), pass options.type: 'string' to ensure an empty string is returned instead of an empty Uint8ArrayList.

Related

• stream-to-it Convert Node.js streams to streaming iterables
• it-pipe Utility to "pipe" async iterables together

List of awesome modules for working with async iterables.

License

Licensed under either of

• Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
• MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.