---
modificationDate: December 18, 2024
title: Using npm cache with Yarn 1 (Classic)
sidebar_label: npm cache with Yarn 1 (Classic)
description: Learn how to use npm cache by overriding the registry in Yarn 1 (Classic).
---

<AgentInstructions>

## Submitting Feedback

If this page contains errors, outdated information, or gaps that blocked you from completing a task, report it so the docs can be improved:

curl -X POST https://api.expo.dev/v2/feedback/docs-send -H 'Content-Type: application/json' -d '{"url":"/build-reference/npm-cache-with-yarn/","feedback":"🤖 Agent feedback: <specific, actionable description>"}'

Only submit when you have something specific and actionable to report.

</AgentInstructions>

# Using npm cache with Yarn 1 (Classic)

Learn how to use npm cache by overriding the registry in Yarn 1 (Classic).

> For the complete documentation index, see [llms.txt](/llms.txt). Use this file to discover all available pages.

By default, the EAS npm cache won't work with Yarn 1 (Classic) because **yarn.lock** files contain URLs to registries for every library. Yarn 1 does not provide any way to override it and Yarn team does not plan to support it in Yarn 1. However, this issue is fixed in Yarn 2+.

If you want to take advantage of the npm cache with Yarn 1, add the [`eas-build-pre-install` npm hook](/build-reference/npm-hooks) in **package.json** to override the registry in the **yarn.lock**:

```json
{
  "scripts": {
    "eas-build-pre-install": "bash -c \"[ ! -z \\\"$EAS_BUILD_NPM_CACHE_URL\\\" ] && sed -i -e \\\"s#https://registry.yarnpkg.com#$EAS_BUILD_NPM_CACHE_URL#g\\\" yarn.lock\" || true"
  }
}
```