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How to migrate from yarn / npm to pnpm

Andrei Chernykh on May 29, 2022

Motivation pnpm is more performant at fetching, resolving, and storing dependencies. My personal experience shows that in some projects ...
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Camilo Martinez •

I'm in a project transition moving from npm to pnpm and it is a nightmare to remember when using each one.

So I decided to create a command to do this. One command will translate to the respective PM.

npmjs.com/package/swpm

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Andrei Chernykh •

Cool stuff!

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Venkata Subbarao Myla •

I found another package which does the same. github.com/antfu/ni

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Camilo Martinez • • Edited

I've tested ni and it is an amazing project too, but have a different approach.

ni focus only on commonly used commands and assign an alias to each one.

The SWPM key differences are:

  • Not limited to some commands or alias, you can use the whole Package Managers.
  • Flags to change his behavior on the fly, like say which Package Manager uses (for example when no lock file exists) or test the command translation.
  • Include a clean command to delete common folders like node_modules.
  • Also, have aliases (like ni) but include another set of commonly used alias like save-dev, exact-version, and others that have been requested by the users.
  • NVM and Volta compatible.
  • Detect lock files, but also work pining manually with the Package Managers (or with the use flag when even no lock file exists).
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Steven Dautrich •

get all time: Invalid package manager specification in package.json; expected a semver version

in my package.json:

"name": "express-demo",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"preinstall": "npx only-allow pnpm",
"test": "echo \"Error: no test specified\" && exit 1"
},
"packageManager": "pnpm@7.1.7>",

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Andrei Chernykh •

It looks like you have a redundant ">" there

"packageManager": "pnpm@7.1.7>",

should be

"packageManager": "pnpm@7.1.7",

Also, this line is optional. It is a node experimental feature. nodejs.org/api/corepack.html

I guess I better remove it from the example

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Sebastian Schlatow •

If I use npm ci in a Jenkins / GitLab pipeline, what command do I need to use with pnpm?

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Andrei Chernykh •

I'm not 100% sure, but according to the docs (docs.npmjs.com/cli/v8/commands/npm-ci) one of the main features of npm ci is If dependencies in the package lock do not match those in package.json, npm ci will exit with an error, instead of updating the package lock.

pnpm docs says In a CI environment, installation fails if a lockfile is present but needs an update.
pnpm.io/cli/install

So, it looks like pnpm i behaves similar to npm ci. Try just pnpm i or pnpm install --frozen-lockfile

Here is a good answer on StackOverflow stackoverflow.com/questions/701545...

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James Palermo •

Can pnmp be set up to allow fall back to npm, say if someone on a locked down/limited device (IoT or something) wants to pull a repo?

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Andrei Chernykh • • Edited

I think it could. Just remove "preinstall": "npx only-allow pnpm",, so the person working with the repo could use npm to install dependencies.
And also, in that case it would make sense to keep packages-lock.json as well.

Note: these are my assumptions. I'm not a maintainer of pnpm and may not know some pitfalls.

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SeongKuk Han •

Hoes does only-allow work? Does that detect when you run a script?

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Arberto99 •

Hi!
After following your tutorial to migrate an existing project from npm to pnpm (without any kind of problem) I run my app with "ng serve", as I was used to do with npm, and I get this errors:

`./src/main.ts - Error: Module build failed (from ./node_modules/.pnpm/@ngtools+webpack@14.2.10_7ypeylls7k.../node_modules/@ngtools/webpack/src/ivy/index.js):
Error: Emit attempted before Angular Webpack plugin initialization.

./src/polyfills.ts - Error: Module build failed (from ./node_modules/.pnpm/@ngtools+webpack@14.2.10_7ypeylls7k.../node_modules/@ngtools/webpack/src/ivy/index.js):
Error: Emit attempted before Angular Webpack plugin initialization.`

Any ideas about how to fix it?
Thanks a lot!

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revoltez •

in my workspace i had the problem you described of importing packages, in npm it worked without modification, but now my package B which depends on package A can't find it, how do i add it in the dependecies?

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Germano Brigido do Nascimento •

For those having problems with moment and dotenv dependencies when migrating from npm to pnpm, simply add a .npmrc file with this content:

public-hoist-pattern[]=*eslint*
public-hoist-pattern[]=*prettier*
public-hoist-pattern[]=@types*
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issue reference

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Ivomar •

The script preinstall is not working for me... I tried to use npm i and also runs

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Jackson Kasi •

hi! is pnpm support all npm packages?

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eitan •

thanks

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Eric •

Is it required to add workspaces?

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David Veszelovszki •

Thanks, loved it!

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Pablo Henrique •

Very informational