add ESM exports in package.json

[akphi]

@krisk We're using Typescript module: Node16 in our project and since Fuse.js ESM does not specify type: module and exports field in package.json, it does not get picked up properly by Typescript. So I would like to add these to the package.json file.

The error I got is something like this, for the following import:

import Fuse from 'fuse.js';

const searchEngine = new Fuse(...

^
This expression is not constructable.
  Type 'typeof import("/Users/user/my-project/node_modules/fuse.js/dist/fuse")' has no construct signatures.ts(2351)

I believe this would help with #541 as I have noted there

For Typescript esm mode, such as Node16, NodeNext, esModuleInterop is not supported in this mode, it's worth if we do something like lukeed/clsx#44 - I have given it an attempt but not quite sure how I can modify the d.ts file accordingly.

[Jack-Works]

Suggested change

	"types": "./dist/fuse.d.ts",
	"import": "./dist/fuse.esm.js",
	"require": "./dist/fuse.common.js"
	"import": {
	"types": "./dist/fuse.d.ts",
	"default": "./dist/fuse.esm.js"
	},
	"require": {
	"types": "./dist/fuse.d.ts",
	"default": "./dist/fuse.common.js"
	}

see microsoft/TypeScript#50466

[akphi]

updated! Thanks for reviewing!

[rchandu]

This would be something that would help us. Is there something I can do to help here on this effort ?

[akphi]

@rchandu seems like there hasn't been active development in this repo for a couple of months now 🤔

[favna]

Suggested change

	"type": "module",
	"exports": {
	".": {
	"types": "./dist/fuse.d.ts",
	"import": "./dist/fuse.esm.js",
	"require": "./dist/fuse.common.js"
	}
	},
	"exports": {
	"types": "./dist/fuse.d.ts",
	"import": "./dist/fuse.esm.js",
	"require": "./dist/fuse.common.js"
	},

The old version was invalid. You cannot just add "type": "module" unless Fuse itself is rewritten to ESM. Also "type": "module" only affects the module itself, not when the module is loaded through node_modules.

Furthermore the subgrouping of "." is not necessary because Fuse doesn't have subpath exports

Lastly, after including this change thus reverting "type": "module" you should also revert the other .cjs related changes.

[akphi]

Thanks for reviewing! I have updated to your suggestions.

It's been a while and I haven't checked again, locally, but I hope this would work well with Typescript + Jest

[favna]

It should. I maintain the Sapphire project and we use this structure in all projects there are it works with a variety of stacks. CJS, ESM, Jest, Vitest, etc

[akphi]

@krisk Could you kindly please take a look at this? Thanks!

[favna]

@akphi expect a PR to your fork with a completely refreshed but also thoroughly tested setup very soon, when you merge that it'll pop up here for Krisk to then review fully.

I noticed my comment above introduced some other issues as well but now I am testing the scenarios:

• CJS (no fluff, super basic package.json)
• MJS (with type module and/or mjs file extension)
• TypeScript with "module": "CommonJS" and "moduleResolution": "Node"` (essentially legacy CJS)
• TypeScript with "module": "Node16" and "moduleResolution": "Node"` (essentially modern CJS)
• TypeScript with "module": "Node16" and "moduleResolution": "Node16"` (essentially modern ESM)

Edit: Only having some trouble with the last one still so I need to figure that out.

[favna]

@akphi I created akphi#1 just now but before it can be merged you need to rebase your own exports branch on top of Krisk/master. Alternatively I could create my own PR targeting Krisk/master from my own fork and we close this PR but that means your contribution credit is lost, your call.

[akphi]

hey @favna, thanks for being super transparent; I really don't mind you carrying that out; all I need is just to have ESM ready :) Thanks so much for the help! - let me know, I'll close it out in favor of your PR

[favna]

I have created #727 so this PR can be closed @akphi