promise-readable
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    6.0.0 • Public • Published

    promise-readable

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    This module allows to convert Readable stream into its promisified version, which returns Promise object fulfilled when open, data, close, end or error events occurred.

    The promisified stream provides async iterator so it is possible to use it with for await...of statement.

    Requirements

    This module requires Node >= 6.

    Installation

    npm install promise-readable

    Additionally for Typescript:

    npm install -D @types/node

    Usage

    const {PromiseReadable} = require("promise-readable")

    Typescript:

    import PromiseReadable from "promise-readable"
    // or
    import {PromiseReadable} from "promise-readable"

    constructor

    const promiseReadable = new PromiseReadable(stream)

    PromiseReadable object requires Readable object to work.

    Example:

    const fs = require("fs")
    const {PromiseReadable} = require("promise-readable")
     
    const stream = fs.createReadStream("/etc/hosts")
    const promiseReadable = new PromiseReadable(stream)

    Typescript:

    import fs from "fs"
    import PromiseReadable from "promise-readable"
     
    const stream = fs.createReadStream("/etc/hosts")
    const promiseReadable = new PromiseReadable(stream)

    stream

    const stream = promiseReadable.stream

    Original stream object.

    Example:

    console.log(promiseReadable.stream.flags)

    read

    const chunk = await promiseReadable.read(chunkSize)

    This method returns Promise which is fulfilled when stream can return one chunk (by read method or data event) or stream is ended (end or close events).

    Example:

    const chunk = await promiseReadable.read(1024)

    Promise returns chunk data if something has been read or undefined value if it is an end of the stream.

    Example:

    for (let chunk; (chunk = await promiseReadable.read()); ) {
      console.log(chunk.length)
    }
    console.log("stream is ended")

    readAll

    const content = await promiseReadable.readAll()

    This method returns Promise which is fulfilled when stream is ended or closed. It is resolved to undefined value if stream is already ended or closed.

    The content from the stream is buffered and then Promise returns this concatenated content.

    setEncoding

    promiseReadable = promiseReadable.setEncoding(encoding)

    By default read and readAll methods returns Buffer objects.

    This method sets the character encoding for data read from the stream. It might be used if original stream does not provide encoding option.

    The method returns this object.

    Example:

    const asBuffer = await promiseReadable.read()
     
    promiseReadable.setEncoding("utf8")
    const asString = await promiseReadable.read()

    once

    const result = await promiseReadable.once(event)

    This method returns Promise which is fulfilled when stream emits event. The result of this event is returned or undefined value if stream is already ended.

    The promise will reject on error.

    Example:

    const fd = await promiseReadable.once("open")
    promiseReadable.stream.pipe(process.stdout)
     
    await promiseReadable.once("close")
     
    promiseReadable.stream.on("data", chunk => console.log(chunk.length))
    await promiseReadable.once("end")
     
    await promiseReadable.once("error") // throws error, undefined if ended

    iterate

    for await (const chunk of promiseReadable.iterate(chunkSize)) {
    }

    This method returns async iterator which returns a content of the stream chunk-by-chunk with defined chunkSize.

    Symbol.asyncIterator

    for await (const chunk of promiseReadable) {
    }

    The PromiseReadable object is an async iterator which returns a content of the stream chunk-by-chunk with the default chunkSize.

    destroy

    promiseReadable.destroy()

    This method calls destroy method on stream and cleans up all own handlers.

    See also

    PromiseWritable, PromiseDuplex, PromiseSocket, PromisePiping.

    License

    Copyright (c) 2017-2019 Piotr Roszatycki mailto:piotr.roszatycki@gmail.com

    MIT

    Install

    npm i promise-readable

    DownloadsWeekly Downloads

    5,272

    Version

    6.0.0

    License

    MIT

    Unpacked Size

    34.6 kB

    Total Files

    10

    Last publish

    Collaborators

    • dex4er