[email protected] failures in typescript and parcel builds and runtime

[isakstarlander]

🐛 bug report

After upgrading date-fns to version 3.6.0 the parcel build started failing, not finding the exported functions. Apart from that the runtime function calls in the dev server fails with provided errors documented in the reproduction repository.

This seems to be a problem for parcel builds in particular, a related issue in date-fns can be found here: date-fns/date-fns#3744

🤔 Expected Behavior

Build should be successful and runtime function calls should work as described in the date-fns repository.

😯 Current Behavior

Build fails unless specifying the alias function name. Runtime the format function throws an error.

Build error:

@parcel/core: node_modules/date-fns/index.mjs does not export 'format'

  /Users/isakstarlander/git/date-fns-parcel-reproduction/formatImport.ts:17:10
    16 | 
  > 17 | import { format } from "date-fns";
  >    |          ^^^^^^
    18 | 
    19 | function renderFormattedDate() {

Runtime error:

TypeError: Cannot read properties of undefined (reading 'y')
    at format.mjs:378:21
    at Array.map (<anonymous>)
    at format (format.mjs:367:6)
    at renderFormattedDate (formatImport.ts:10:26)
    at ghM9m.date-fns (formatImport.ts:21:1)
    at newRequire (index.0dd3d9d0.js:71:24)
    at index.0dd3d9d0.js:122:5
    at index.0dd3d9d0.js:145:3

🔦 Context

This issue prevents us from upgrading date-fns to the latest supported major version.

💻 Code Sample

Reproduction repository: https://github.com/Milkywire/date-fns-parcel-reproduction

🌍 Your Environment

Software	Version(s)
Parcel	2.12.0
date-fns	3.6.0
Node	18
Operating System	MacOS

[Poky85]

In the meantime this is workaround:

import format from 'date-fns/format';

[conan]

The workaround doesn't seem to work in v4.1.0, I can't find any way of using v4 of date-fns with parcel:

import {format} from 'date-fns/format';

gives:

@parcel/core: node_modules/date-fns/format.js does not export 'format'

The workaround causes my typescript compilation to fail:

import format from "date-fns/format";

tsc --no-emit
error TS2613: Module '"node_modules/date-fns/format"' has no default export. Did you mean to use 'import { format } from "node_modules/date-fns/format"' instead?

Software	Version(s)
Parcel	2.12.0
Node	v20.14.0
npm	10.9.0
date-fns	4.1.0
OS	Ubuntu 22.04.5 LTS

[ryanking1809]

I noticed this issue converting some javascript to typescript. And for some reason it doesn't seem to be a problem with javascript. Not ideal, but with that in mind, I've managed to work around it by importing and exporting format via a .js file.

format.js

import { format } from 'date-fns';
export { format };

[kai-dorschner-twinsity]

The question is, is it a problem with date-fns or with the parcel resolver? I can't wrap my head around it. The package.json of date-fns links many (possibly unnecessarily explicit and even more possibly broken) exports https://github.com/date-fns/date-fns/blob/6c70ac6d073ebe869e42795f5e71dfecf5abbea0/package.json#L21

Edit:
The imports work when you add the --no-scope-hoist parameter to the parcel bundle process.

[peguimasid]

Any updated on this? I think this issue is related to date-fns/date-fns#3670

[Saturn]

Ran into this issue too. The workaround e.g. importing formatters, longFormatters explicitly so they don't get (wrongly) left out of the bundle seems to be working in my case.

Presumably other bundlers don't have this issue with date-fns tree shaking 🤷‍♂️🤷‍♂️