Separate `index.js` and `test.js` into different files

[tommy-mitchell]

Per #233.

Tasks:

• [X] Target Node 14
• [X] Update dependencies, fix breaking changes
• [X] Separate into different source files
• [x] Separate tests, consolidate via macros
• [ ] ~Add doc comments~ -> separate PR

Miscellaneous fixes:

• Fixed extraneous indents in fixtures
• Fixed extraneous leading space in readme
• Fixed test dealing with process.title, added note to readme/index.d.ts about overriding options.pkg (needs better wording)

[sindresorhus]

This looks good so far 👍

[sindresorhus]

You can target Node.js 16.

---

Here's what we may be able to take advantage of:

Node.js 16

• private class methods and accessors
• import {setTimeout} from 'node:timers/promises';
• import stream from 'node:stream/promises';
• Native AggregateError.
• String.prototype.replaceAll
• Promise.any
• Array/String#at (Node v16.6.0)
• Object.hasOwn (v16.10)

Node.js 14

• private class fields
• Top-level await
  • Get rid of all (async () => {})()
• crypto.randomInt (Node.js 14.10)
• Optional chaining
• Nullish Coalescing
• import fs from 'node:fs/promises';
• crypto.randomUUID() (Node.js 14.17)
• AbortController signal option (Node.js 14.18)

[tommy-mitchell]

You can target Node.js 16.

I'll do this in a separate PR then, the diff for this one is already pretty large and I'd like the changes from the improvements to be easier to see.

By the way, is this list posted anywhere else? It's a nice checklist for a project bumping their Node version.

[sindresorhus]

By the way, is this list posted anywhere else? It's a nice checklist for a project bumping their Node version.

It's just my personal list. I think the Node.js team may post something similar on new major versions.

[sindresorhus]

I'll do this in a separate PR then, the diff for this one is already pretty large and I'd like the changes from the improvements to be easier to see.

👍

[tommy-mitchell]

I've split up associated tests from test.js into their own files and consolidated via macros or utils where possible, especially for handling fixtures. Some more could be done here, but I think it's good enough for now.

[sindresorhus]

Can you fix the merge conflict?

[tommy-mitchell]

Should be good now