Enhancement: [no-require-imports] Add option allowJson

[remcohaszing]

Before You File a Proposal Please Confirm You Have Done The Following...

• I have searched for related issues and found none that match my proposal.
• I have searched the current rule list and found no rules that match my proposal.
• I have read the FAQ and my problem is not listed.

My proposal is suitable for this project

• I believe my proposal would be useful to the broader TypeScript community (meaning it is not a niche proposal).

Link to the rule's documentation

https://typescript-eslint.io/rules/no-require-imports/

Description

If module in tsconfig.json is set to Node16, TypeScript 4.7 will convert import … = require('…') statements to require calls created using _createRequire.

As long as import assertions are not allowed in Node.js, I believe this is a nice syntax to read package.json files.

I propose to add an option named allowJson to no-require-imports that allows require imports of JSON files.

Fail

import lodash = require('lodash')
import lib = require('./lib')

Pass

These are currently also errored on


import lodashPkg = require('lodash/package.json')
import pkg = require('./package.json')

Additional Info

In:

import pkg = require('./package.json')

console.log(pkg.version)

Out:

import { createRequire as _createRequire } from "module";
const __require = _createRequire(import.meta.url);
const pkg = __require("./package.json");
console.log(pkg.version);

TypeScript playground

[Josh-Cena]

As long as import assertions are not allowed in Node.js

Import assertions are stable and unflagged in Node. JSON modules are experimental but IMO there's little reason to not use it for non-library code.

[remcohaszing]

As long as import assertions are not allowed in Node.js

Import assertions are stable and unflagged in Node. JSON modules are experimental but IMO there's little reason to not use it for non-library code.

I gave it a try and it’s not supported in Node.js 14.

It is supported in Node.js 18, but it prints a warning stating it’s experimental. This doesn’t look great for CLIs.

[Josh-Cena]

Indeed, many reasons to stop using Node 14 😄 I do use it personally and I find the fact that the code is fully ESM more pleasing than that I get a warning.

[remcohaszing]

I can’t argue with that!

However, Node.js 14 is still a supported LTS, and I believe this TypeScript syntax is a nice way to deal with JSON files for now.

[bradzacher]

Given that node14 will EOL in april next year - is it worth adding an option to support the old way of doing things when people will be moving to the new way relatively soon?

Looking into it - it's supported in node 16 behind a flag, but node16 will EOL a few months after node 14. It's fully supported in node18, which will EOL in 3 years.

I'm not entirely convinced that an option is the best of ideas given the above and given how infrequent a usecase it is to directly import JSON.

[remcohaszing]

I can think of one legitimate reason to import package.json, which is to use certain metadata inside a GUI About screen, CLI --version flag, collect metadata for issue reports or analytics. I think typically libraries should avoid importing JSON.