File generator

Generate fake in-memory files for varying sizes

This package allows you generate fake in-memory files for varying sizes. The generated file can be used during testing to test the file uploads functionality of your Node server.

• Support for docx, xlsx, pdf, png, jpg, and gif files.
• Passes the magic number file validation.
• The file contents is kept in-memory Buffer. No files are written to the disk.

Installation

Install the package from the npm registry as follows.

npm i @poppinss/file-generator

# Yarn
yarn add @poppinss/file-generator

Usage

Use the exported functions as follows.

import { generatePng } from '@poppinss/file-generator'

const {
  contents,
  size,
  mime,
  name
} = await generatePng('1mb')

• contents is a buffer.
• size is the size of the file in bytes.
• mime is the mime type for the generated file.
• name is a randomly assigned unique name to the file.

You can also define a custom file name as the second argument.

await generatePng('1mb', 'avatar.png')

Usage with form-data

You can pass the generated content to an instance of form data as follows.

import FormData from 'form-data'

const form = new FormData()
const file = await generatePng('1mb')

form.append('avatar', file.contents, {
  filename: file.name,
  contentType: file.mime,
  knownLength: file.size,
})

Points to note

• Only the first few bytes of the files are valid and rest of the bytes are empty. Therefore, further processing of the files will not work. For example: If you open the PDF file to read its content on the server, then using this package is not the right choice.
• Every file type has minimum bytes and you cannot generate files smaller than that. This is done to keep the initial bytes valid and them pass the standard validation rules.