ESLint 9 not supported by @lwc/eslint-plugin-lwc

[gdecaen-klint]

Summary

After the creation of a SFDX project, I have an error when I run "npm i" command

Steps To Reproduce:

1. Create a new SFDX project
2. Run npm i command on terminal

Expected result

NPM modules should be installed correctly

Actual result

npm error code ERESOLVE
npm error ERESOLVE unable to resolve dependency tree
npm error
npm error While resolving: salesforce-app@1.0.0
npm error Found: eslint@9.11.1
npm error node_modules/eslint
npm error dev eslint@"^9.9.1" from the root project
npm error peer eslint@"^7.5.0 || ^8.0.0 || ^9.0.0" from @babel/eslint-parser@7.25.7
npm error node_modules/@babel/eslint-parser
npm error peer @babel/eslint-parser@"^7" from @lwc/eslint-plugin-lwc@1.8.2
npm error node_modules/@lwc/eslint-plugin-lwc
npm error dev @lwc/eslint-plugin-lwc@"^1.1.2" from the root project
npm error
npm error Could not resolve dependency:
npm error peer eslint@"^7 || ^8" from @lwc/eslint-plugin-lwc@1.8.2
npm error node_modules/@lwc/eslint-plugin-lwc
npm error dev @lwc/eslint-plugin-lwc@"^1.1.2" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
npm error to accept an incorrect (and potentially broken) dependency resolution.

Additional information

VS Code Version: Version: 1.94.0 (user setup)

SFDX CLI Version: @salesforce/cli/2.60.13 win32-x64 node-v20.17.0

OS and version: Windows_NT x64 10.0.26100

[codybrom]

This issue is still present in February 2025 even if I update @lwc/eslint-plugin-lwc to 2.1.0.

npm error code ERESOLVE
npm error ERESOLVE unable to resolve dependency tree
npm error
npm error While resolving: salesforce-app@1.0.0
npm error Found: eslint@9.20.1
npm error node_modules/eslint
npm error   dev eslint@"^9.9.1" from the root project
npm error   peer eslint@"^7.5.0 || ^8.0.0 || ^9.0.0" from @babel/eslint-parser@7.26.8
npm error   node_modules/@babel/eslint-parser
npm error     peer @babel/eslint-parser@"^7" from @lwc/eslint-plugin-lwc@2.1.0
npm error     node_modules/@lwc/eslint-plugin-lwc
npm error       dev @lwc/eslint-plugin-lwc@"^2.1.0" from the root project
npm error
npm error Could not resolve dependency:
npm error peer eslint@"^7 || ^8" from @lwc/eslint-plugin-lwc@2.1.0
npm error node_modules/@lwc/eslint-plugin-lwc
npm error   dev @lwc/eslint-plugin-lwc@"^2.1.0" from the root project
npm error
npm error Fix the upstream dependency conflict, or retry
npm error this command with --force or --legacy-peer-deps
npm error to accept an incorrect (and potentially broken) dependency resolution.

[codybrom]

My temp fix is to use an older version of eslint:

"eslint": "^8",

[james-ef]

@pozil @daphne-sfdc @mingxuanzhangsfdx Hi - is there any chance of anyone from salesforce looking at this. We just had to revert the dependabot recommendations for eslint due to this (as version 9 of eslint broke the dependencies)

[pozil]

@james-ef, I believe that the LWC tooling team is working on this request here: salesforce/eslint-config-lwc#128
Feel free to chime in.

[pozil]

Hi all, great news: I just got word that support for ESLint v9 is finally here.
See this PR for a migration example: trailheadapps/ebikes-lwc#803

[gdecaen-klint]

I am not able to update package.json as long as package eslint-plugin-aura does not support ESLint v9 forcedotcom/eslint-plugin-aura#43

[pozil]

@gdecaen-klint stay tuned: I heard that the LWC team is working on this.

[pozil]

For reference, the PR that brings ESLint v9 to Aura is almost ready: forcedotcom/eslint-plugin-aura#44

[ravijayaramappa]

Just released a new version of @salesforce/eslint-plugin-aura. Please give it a try and let us know your feedback. https://www.npmjs.com/package/@salesforce/eslint-plugin-aura/v/3.0.0-beta.1

[pozil]

Hi all, good news, support for ESLint 9 is now included in the latest version 64.2.0. It may take a couple of days to get to prod.

FYI @mshanemc we can close this issue.