metro-cache

library0.84.4jsnpmunverified

Metro is the JavaScript bundler for React Native applications. The metro-cache package provides caching layers for Metro, enabling faster builds by storing and retrieving previously computed results. Version 0.84.4 is the current stable release. It is updated frequently alongside Metro releases. Key differentiators include multiple cache backends (file, HTTP, etc.) and integration with Metro's build pipeline. It is part of the official Metro monorepo maintained by Meta.

devops

npm install metro-cache

github ↗package ↗homepage ↗

INSTALL

IMPORT

SIG · METRO-CACHE

metro-cache

devopsjavascriptv0.84.4

harness data pending

Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

CacheStore

✓ import { CacheStore } from 'metro-cache'

✗ const CacheStore = require('metro-cache').CacheStore

ESM-only in recent versions; CommonJS require is not recommended but may still work.

FileStore

✓ import { FileStore } from 'metro-cache'

Default export is not available; always use named import.

HttpStore

✓ import { HttpStore } from 'metro-cache'

✗ import HttpStore from 'metro-cache'

HttpStore is a named export, not the default export.

Shows how to create a FileStore and use CacheStore to set and get cached values.

import { FileStore, CacheStore } from 'metro-cache'; const store = new FileStore({ root: '/tmp/cache' }); const cache = new CacheStore(store); async function example() { const key = 'some-key'; const value = { data: 'cached content' }; await cache.set(key, value); const retrieved = await cache.get(key); console.log(retrieved); } example().catch(console.error);

Debug

Known issues

breakingIn version 0.80+, CacheStore API changed: set/get methods now return promises instead of being synchronous.

fix

Ensure you use await or .then() when calling set and get.

affects: >=0.80.0

gotchaFileStore requires a writable directory. Default root may not exist in some environments (e.g., serverless).

fix

Always provide an explicit root directory that exists and is writable.

affects: all

deprecatedHttpStore is deprecated in favor of using a custom store with HTTP backend; may be removed in future versions.

fix

Consider implementing a custom store using the CacheStore interface or use FileStore with a shared filesystem.

affects: >=0.84.0

gotchaCache keys must be strings or Buffers; other types will be coerced and may cause collisions.

fix

Always use string keys, preferably hashed or serialized.

affects: all

Errors

Common errors & fixes

Error: ENOENT: no such file or directory, mkdir '/some/path'

The root directory for FileStore does not exist.

fix

Create the directory before initializing FileStore or set root to an existing directory.

TypeError: cache.set is not a function

Using a synchronous call on an async method without awaiting.

fix

Call cache.set with await or handle the promise.

Error: Invalid cache key type. Expected string or Buffer.

Non-string/non-Buffer key passed to set or get.

fix

Convert key to string, e.g., JSON.stringify or toString().

Upgrade

Version history

0.84.4latest on npm

Audit

Dependencies

metro-corerequiredCore Metro types and utilities

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/facebook/metro ↗

packagemetro-cache ↗

homepagehttps://github.com/facebook/metro#readme ↗