form-auto-content

Build a form payload without caring if it should be application/x-www-form-urlencoded or multipart/form-data. It works with Fastify and light-my-request too!

Install

npm install form-auto-content

Usage

This module will transform your JSON to a payload ready to submit to an HTTP server! The autosense feature will check if there is a stream or a buffer as input and it will act accordingly returning a multipart/form-data stream; otherwise it will create a x-www-form-urlencoded string.

The module return a JSON like this:

{
  payload: Stream, // the data Stream
  headers: {} // a JSON with the `content-type` field set
}

x-www-form-urlencoded

const formAutoContent = require('form-auto-content')

const myForm = formAutoContent({
  field1: 'value1',
  field2: ['value2', 'value2.2'] // array are supported too!!
})

myForm.payload // Stream of the string in application/x-www-form-urlencoded format
myForm.headers // JSON with the `content-type` field set

multipart/form-data

const formAutoContent = require('form-auto-content')

const myForm = formAutoContent({
  field1: 'value1',
  field2: ['value2', 'value2.2'], // array are supported too!!
  myFile: fs.createReadStream('the-file.xml'),
  multipleFiles: [fs.createReadStream('file1.xml'), fs.createReadStream('file2.xml')],
  wowBuffer: Buffer.from('a long string'),

  // the file options are supported too:
  myRenamedFile: {
    value: fs.createReadStream('./foo.md'),
    options: {
      filename: 'bar.md',
      contentType: 'text/markdown'
    }
  },
  // also in arrays!
  renamedArray: [
    {
      value: fs.createReadStream('./one.json'),
      options: { filename: 'foo.json' }
    },
    {
      value: fs.createReadStream('./two.json'),
      options: { filename: 'bar.json' }
    }
  ]
})

myForm.payload // Stream in multipart/form-data format
myForm.headers // JSON with the `content-type` field set to multipart/form-data

Options

To customize the output field names, add an extra option object with the payload and headers string!

const formAutoContent = require('form-auto-content')

const option = { payload: 'body', headers: 'head' }
const myCustomForm = formAutoContent({
  field1: 'value1',
  field2: ['value2', 'value2.2'] // array are supported too!!
}, option)

myForm.body // Stream of the string in application/x-www-form-urlencoded format
myForm.head // JSON with the `content-type` field set

Typescript

This module ships with a handwritten TypeScript declaration file for TS support. The declaration exports a single function.

import formAutoContent from 'form-auto-content';

When an options object is provided, the result types will be accurately inferred:

import formAutoContent from 'form-auto-content';

const option = {
  payload: 'body',
  headers: 'head',
  forceMultiPart: true,
} as const;

const myCustomForm = formAutoContent({
  field1: 'value1',
  field2: ['value2']
}, option);

myCustomForm.body // ok
myCustomForm.head // ok

myCustomForm.payload // Typescript error: property 'payload' does not exists in type...

License

Licensed under MIT.