node-fetch-patch

a nodejs fetch polyfill/patch, ensures the availability across environments and versions.

How does it work?

import the main file (for v10.0 - 20.8.1)

const fetch = require('./node-fetch-patch');

or the other one to use with nodejs versions below 10 (since async import is not available)

const fetch = require('./node-fetch-patch-all');

• Firstly, the module checks if nodejs native fetch api (built-in) is supported.
• If not, it checks for a node-fetch installation(specifically below 2.6.1), and tries to do a CommonJS require.
• If it doesn't work, tries to import node-fetch with async import function. This works for the verions above 2.6.1.
• If any of those work, it installs node-fetch using node package manager, then restarts the script/console.

How do I know where 'fetch' was imported from?

node-fetch-patch will add a some properties to let you know this:

• environment variable: process.env.PATCHTYPE
• global variable: global.patchType
• along with a property: fetch.patchType

For example, if the fetch function was imported from nodejs native fetch api:

> console.log(fetch)
[AsyncFunction: fetch] { patchType: 0 }

> console.log(global.patchType)
0

> console.log(process.env.PATCHTYPE)
'0'

From node-fetch versions below 2.6.1 using CommonJS require:

> console.log(fetch)
[AsyncFunction: fetch] { patchType: 2 }

> console.log(global.patchType)
2

> console.log(process.env.PATCHTYPE)
'2'

From node-fetch versions above 2.6.1 using async import (unavailable in node-fetch-patch-all.js):

> console.log(fetch)
[AsyncFunction: fetch] { patchType: 3 }

> console.log(global.patchType)
3

> console.log(process.env.PATCHTYPE)
'3'

if no fetch function found (this means node-fetch-patch is installing it and will restart the main process or node console):

> console.log(fetch)
{ patchType: undefined }

> console.log(global.patchType)
undefined

> console.log(process.env.PATCHTYPE)
undefined

Or if node-fetch-patch couldn't export the fetch function (mostly because of an error):

> console.log(fetch)
{ patchType: null }

> console.log(global.patchType)
null

> console.log(process.env.PATCHTYPE)
'null'