it-concat

it-concat

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

Install

npm install it-concat

Usage

Concat buffers to a single BufferList:

const concat = require('it-concat')

const fs = require('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 BufferList
console.log(chunks)
/*
BufferList {
  _bufs: [ <Buffer 48 65 6c 6c 6f 20 57 6f 72 6c 64 21> ],
  length: 12
}
*/
console.log(chunks.toString())
// Hello World!

Concat buffers to a single string:

const concat = require('it-concat')

const fs = require('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 buffer. This is necessary because the source data is buffer(s).
const chunks = await concat(fs.createReadStream('./test.txt'), { type: 'string' })

console.log(chunks)
// Hello World!

Concat strings to a single string:

const concat = require('it-concat')

const fs = require('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 buffer(s).
const chunks = await concat(fs.createReadStream('./test.txt', { encoding: 'utf8' }))

console.log(chunks)
// Hello World!

API

const concat = require('it-concat')

concat(source, options?): Promise

Concat all buffers or strings yielded from the async iterable source into a single BufferList or string.

• source (AsyncIterable<Buffer | BufferList | 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 'buffer' for a BufferList.

Returns a Promise that resolves to a BufferList or string.

If options.type is not passed the type of the objects yielded from the source is detected and a BufferList or string is returned appropriately. If the source does not yield anything an empty BufferList 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 BufferList.

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.

Contribute

Feel free to dive in! Open an issue or submit PRs.

License

MIT © Alan Shaw

Changelog

3.0.0 (2022-10-18)

⚠ BREAKING CHANGES

• this module is now ESM-only

Features

• convert to typescript (#20) (51b56f1)