> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Invalidate Cache > Explains using the Jenkins Job Cacher plugin with package-lock.json to invalidate and refresh dependency caches, keeping builds fast and preventing stale node_modules. In this lesson we show how to invalidate a Jenkins dependency cache automatically whenever project dependencies change — specifically when `package-lock.json` (or `yarn.lock`) is updated. This ensures fast builds when dependencies are unchanged, and safe cache refreshes when they are not. A blue-to-teal gradient slide with subtle diamond shapes and centered white text that reads "Invalidate Caching." A small "© Copyright KodeKloud" appears in the bottom-left. The Job Cacher plugin supports a cache-validity mechanism using a cache-validity deciding file (for example: `package-lock.json`). When that file changes, the plugin computes a new hash and decides whether an existing cache is still valid. Below is the Jenkins pipeline snippet used to cache `node_modules` and to make `package-lock.json` the cache-validity file. ```groovy theme={null} options { timestamps() } steps { cache(maxCacheSize: 550, caches: [ arbitraryFileCache( cacheName: 'npm-dependency-cache', cacheValidityDecidingFile: 'package-lock.json', includes: '**/*', path: 'node_modules') ]) { sh 'node -v' sh 'npm install --no-audit' stash(includes: 'node_modules/', name: 'solar-system-node-modules') } } ``` Demonstration — add a dependency locally in the repository: ```bash theme={null} root@jenkins-controller-1 in solar-system on ⬢ feature/advanced-demo via ⬢ v20.16.0 on ☁ (us-east-2) ➜ npm install localtunnel ``` npm reports the new installation: ```console theme={null} added 7 packages, and audited 366 packages in 2s 45 packages are looking for funding run `npm fund` for details 10 vulnerabilities (1 low, 4 moderate, 5 high) To address issues that do not require attention, run: npm audit fix To address all issues (including breaking changes), run: npm audit fix --force Run `npm audit` for details. ``` Installing the dependency updates both `package.json` and `package-lock.json`. When you commit and push these changes the pipeline triggers, and the Job Cacher plugin computes a hash of `package-lock.json` and compares it with the hash associated with the stored cache archive. Representative pipeline logs for the two outcomes: 1. Cache is up-to-date and is restored: ```console theme={null} [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] Searching cache in job specific caches... [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] got hash a47b9ef02dbc79db72ab6385105e0142 for cacheValidityDecidingFile(s) - actual file(s): /var/lib/jenkins/workspace/solar-system_feature_advanced-demo/package-lock.json [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] Found cache in job specific caches [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] Restoring cache... [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] Cache restored in 771ms + node -v v22.6.0 + npm install --no-audit up to date in 1s 44 packages are looking for funding run `npm fund` for details Stashed 4993 file(s) [Cache for node_modules (npm-dependency-cache) ...] Skip cache creation as the cache is up-to-date ``` 2. `package-lock.json` changed — cache is outdated and is recreated: ```console theme={null} [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] Searching cache in job specific caches... [Cache for node_modules (npm-dependency-cache) with id 3ec03583f8eaec275cb2183db769ff47] got hash 5a15d94c8bab08a6882fddf4b8ef16c2 for cacheValidityDecidingFile(s) - actual file(s): /var/lib/jenkins/workspace/solar-system_feature_advanced-demo/package-lock.json [Cache for node_modules (npm-dependency-cache) ...] cacheValidityDecidingFile configured, but previous hash does not match - cache outdated [Cache for node_modules (npm-dependency-cache) ...] Skip restoring cache as no up-to-date cache exists + node -v v22.6.0 + npm install --no-audit added 7 packages in 2s 45 packages are looking for funding run `npm fund` for details Stashed 5131 file(s) [Cache for node_modules (npm-dependency-cache) ...] Creating cache... [Cache for node_modules (npm-dependency-cache) ...] Cache created in 2179ms ``` How it works (step-by-step) * The plugin computes a hash of the configured cache-validity file(s) (in this example: `package-lock.json`) in the current workspace. * It compares that hash with the hash associated with the existing cache for this job. * If the hashes match, the plugin restores the cache and the build step finishes quickly (for example: `npm install` reports "up to date"). * If the hashes differ, the plugin treats the cache as outdated, skips restoration, runs the install to produce up-to-date `node_modules`, then creates a new cache using the new hash. * Subsequent builds with the same `package-lock.json` content will restore the newly created cache until the lockfile changes again. Quick reference table | Condition | Plugin action | Typical result | | --------------------------------------------: | ------------------------------------------- | --------------------------------------- | | `package-lock.json` hash matches stored cache | Restore cache | `npm install` is fast — "up to date" | | `package-lock.json` hash differs | Skip restore, run install, create new cache | Fresh `node_modules` created and cached | Use `cacheValidityDecidingFile` (for example, `package-lock.json` or `yarn.lock`) so the Job Cacher invalidates dependency caches whenever the lockfile changes. This maintains build speed for unchanged dependencies while preventing stale or incompatible modules from being reused. Links and references * Job Cacher plugin (Jenkins) — check the plugin documentation in your Jenkins instance or the plugin site for configuration details. * Jenkins pipeline documentation: [https://www.jenkins.io/doc/book/pipeline/](https://www.jenkins.io/doc/book/pipeline/) * npm lockfile formats and behavior: [https://docs.npmjs.com/cli/v9/configuring-npm/package-lock-json](https://docs.npmjs.com/cli/v9/configuring-npm/package-lock-json) That's all for now.