writable-wrapper

This TypeScript library for Node.js offers a writable stream implementation that forwards all data to another Writable, the "target".

This is useful for adding functionality to a Writable without patching the original object. WritableWrapper can be extended easily and will handle the forwarding of any data written to it, while not making that data available to any external consumer.

Transform streams are unsuitable for that purpose, since data listeners can always be attached.

Install

npm i writable-wrapper

Usage

Simple Example

import fs from 'fs'
import WritableWrapper from 'writable-wrapper'

const wrapper = new WritableWrapper(fs.createWriteStream('file.txt'))

Custom Class Example

Of course, this functionality is really only useful for custom object types:

import fs from 'fs'
import WritableWrapper from 'writable-wrapper'

// Class for new items. You can write data, and when done, store the item.
// Not calling 'store' dismisses the item.
class NewlyCreatedItem extends WritableWrapper {
  store (): void {
    this.end(function () {
      // store this item
    })
  }
}

// ...

const item = new NewlyCreatedItem(fs.createWriteStream('file.txt'))
item.write('hello world', 'utf8')
item.store()