[functions] use JSON serialization in InMemoryCache for RuntimeCache consistency by kldavis4 · Pull Request #14751 · vercel/vercel

kldavis4 · 2026-01-27T15:41:35Z

TL;DR

Updated InMemoryCache to use JSON serialization for cache values, ensuring consistency with RuntimeCache.

What changed?

Modified InMemoryCache to serialize values with JSON.stringify() when storing and deserialize with JSON.parse() when retrieving
Changed the value type in CacheEntry interface from unknown to string to reflect the serialized storage format
Added comprehensive unit tests to verify serialization behavior and ensure compatibility with RuntimeCache

How to test?

Run the new unit tests that verify:

Basic get/set functionality for various data types
JSON serialization behavior (Date objects, undefined values, Maps, Sets, etc.)
TTL expiration functionality
Cache deletion and tag expiration

pnpm test packages/functions/test/unit/cache/in-memory-cache.test.ts

Why make this change?

This change ensures consistent behavior when switching between cache implementations (in-memory for development, remote for production). Previously, the InMemoryCache stored values directly while RuntimeCache used JSON serialization, leading to inconsistencies with types that don't survive JSON round-trips like Date, Map, Set, and undefined. Now both implementations handle data types the same way, preventing unexpected behavior when moving between environments.

…consistency

changeset-bot · 2026-01-27T15:41:51Z

🦋 Changeset detected

Latest commit: 66e20f8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@vercel/functions	Patch

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kldavis4 · 2026-01-27T15:41:54Z

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github-actions · 2026-01-27T15:42:39Z

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github-actions · 2026-01-27T15:43:05Z

🧪 Unit Test Strategy

Comparing: d26ce3f → 66e20f8 (view diff)

Strategy: Affected packages only

✅ Only testing packages that have been modified or depend on modified packages.

Affected packages - 12 (29%)

@vercel/client
@vercel/edge
@vercel/elysia
@vercel/express
@vercel/fastify
@vercel/functions
@vercel/h3
@vercel/hono
@vercel/koa
@vercel/nestjs
@vercel/node
vercel

Unaffected packages - 29 (71%)

@vercel-internals/get-package-json
@vercel/backends
@vercel/build-utils
@vercel/cervel
@vercel/cli-auth
@vercel/config
@vercel/detect-agent
@vercel/error-utils
@vercel/firewall
@vercel/frameworks
@vercel/fs-detectors
@vercel/gatsby-plugin-vercel-builder
@vercel/go
@vercel/hydrogen
@vercel/introspection
@vercel/next
@vercel/oidc
@vercel/oidc-aws-credentials-provider
@vercel/python
@vercel/python-analysis
@vercel/redwood
@vercel/related-projects
@vercel/remix-builder
@vercel/routing-utils
@vercel/ruby
@vercel/rust
@vercel/static-build
@vercel/static-config
examples

Results

Unit tests: Only affected packages will run unit tests
E2E tests: Handled separately (Version Packages PRs or run-e2e-tests label)
Type checks: Only affected packages will run type checks

This comment is automatically generated based on the affected testing strategy

packages/functions/src/cache/in-memory-cache.ts

JSON.stringify(undefined) returns JavaScript's undefined (not a string), which causes JSON.parse() to throw SyntaxError in get(). Coerce undefined values to null to prevent this error. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

This PR was opened by the [Changesets release](https://github.com/changesets/action) GitHub action. When you're ready to do a release, you can merge this and the packages will be published to npm automatically. If you're not ready to do a release yet, that's fine, whenever you add more changesets to main, this PR will be updated. # Releases ## vercel@50.10.0 ### Minor Changes - feat(cli): Add webhooks command for managing webhooks ([#14789](#14789)) Adds a new `webhooks` command to the Vercel CLI with the following subcommands: - `webhooks ls` - List all webhooks with optional `--format json` output - `webhooks get <id>` - Get details of a specific webhook with optional `--format json` output - `webhooks create <url> --event <event>` - Create a new webhook with specified events - `webhooks rm <id>` - Remove a webhook with `--yes` flag to skip confirmation Webhook event types are fetched dynamically from the OpenAPI spec to stay in sync with the API. - Added experimental services support in the CLI new project flow. When `VERCEL_USE_EXPERIMENTAL_SERVICES=1` is set and a project's `vercel.json` contains `experimentalServices`, the CLI will detect and display the configured services during project setup, automatically selecting the "services" framework preset. ([#14776](#14776)) ### Patch Changes - Improve logsv2 command output format with compact single-line display, text-based level labels, dynamic column widths, and smart date display ([#14767](#14767)) - Skip update check when running on Vercel to prevent unnecessary worker spawning in build container ([#14794](#14794)) - fix --help exit codes for marketplace commands ([#14834](#14834)) - Updated dependencies \[[`687f73cebb6ae1cdd7c7feb0910967de99a17ad6`](687f73c), [`e7c5d5fd41e124ef7314978b351696d130e89917`](e7c5d5f), [`c3104a1ae9dbf9048e08bb2fa85605a95b254876`](c3104a1), [`b029736b4be8dac135bef77283f47e1450faf0a9`](b029736), [`d36c1ad3ddaf9303041e61a0a41d973b02007988`](d36c1ad), [`5b31b133970539986ff9e98013d2c364536bd0b5`](5b31b13)]: - @vercel/next@4.15.21 - @vercel/python@6.5.0 - @vercel/remix-builder@5.5.10 - @vercel/backends@0.0.25 - @vercel/static-build@2.8.28 - @vercel/node@5.5.28 - @vercel/express@0.1.36 ## @vercel/python@6.5.0 ### Minor Changes - vendor Python runtime dependencies ([#14827](#14827)) - Bump vercel-runtime version automatically on its releases ([#14842](#14842)) ## @vercel/python-analysis@0.3.0 ### Minor Changes - initial implementation of Python semantic analysis in Rust ([#14690](#14690)) ## @vercel/backends@0.0.25 ### Patch Changes - Improve handling of cjs/esm interop during imports ([#14798](#14798)) ## @vercel/cervel@0.0.12 ### Patch Changes - Improve handling of cjs/esm interop during imports ([#14798](#14798)) - Updated dependencies \[[`d36c1ad3ddaf9303041e61a0a41d973b02007988`](d36c1ad)]: - @vercel/backends@0.0.25 ## @vercel/express@0.1.36 ### Patch Changes - Updated dependencies \[[`d36c1ad3ddaf9303041e61a0a41d973b02007988`](d36c1ad)]: - @vercel/cervel@0.0.12 - @vercel/node@5.5.28 ## @vercel/fs-detectors@5.7.20 ### Patch Changes - Added experimental services support in the CLI new project flow. When `VERCEL_USE_EXPERIMENTAL_SERVICES=1` is set and a project's `vercel.json` contains `experimentalServices`, the CLI will detect and display the configured services during project setup, automatically selecting the "services" framework preset. ([#14776](#14776)) ## @vercel/functions@3.4.1 ### Patch Changes - Fix InMemoryCache to use JSON serialization for consistency with RuntimeCache ([#14751](#14751)) InMemoryCache now serializes values with `JSON.stringify()` on set and deserializes with `JSON.parse()` on get, matching the behavior of RuntimeCache. This ensures consistent behavior when switching between cache implementations (e.g., in-memory for development, remote for production), particularly for types that don't survive JSON round-trips like `Date`, `Map`, `Set`, and `undefined`. ## @vercel/introspection@0.0.11 ### Patch Changes - Updated dependencies \[[`d36c1ad3ddaf9303041e61a0a41d973b02007988`](d36c1ad)]: - @vercel/backends@0.0.25 ## @vercel/next@4.15.21 ### Patch Changes - Strip routes-manifest.json for determinism ([#14783](#14783)) - Update Next.js adapter version ([#14801](#14801)) ## @vercel/remix-builder@5.5.10 ### Patch Changes - [remix] Prevent 404 responses from being cached with immutable headers ([#14828](#14828)) ## @vercel/python-runtime@0.3.0 ### Minor Changes - vendor Python runtime dependencies ([#14827](#14827)) Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

[functions] use JSON serialization in InMemoryCache for RuntimeCache …

92faa52

…consistency

kldavis4 marked this pull request as ready for review January 27, 2026 15:42

kldavis4 requested review from a team as code owners January 27, 2026 15:42

vercel bot deployed to Preview January 27, 2026 15:42 View deployment

vercel bot reviewed Jan 27, 2026

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packages/functions/src/cache/in-memory-cache.ts Outdated Show resolved Hide resolved

kldavis4 and others added 2 commits January 27, 2026 15:56

update changeset

6eb2f2c

vercel bot deployed to Preview January 27, 2026 21:03 View deployment

smaeda-ks approved these changes Jan 29, 2026

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kldavis4 merged commit 22e856f into main Jan 31, 2026
233 of 235 checks passed

kldavis4 deleted the kd/01-27-_functions_use_json_serialization_in_inmemorycache_for_runtimecache_consistency branch January 31, 2026 05:20

vercel-release-bot mentioned this pull request Jan 31, 2026

Version Packages #14813

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[functions] use JSON serialization in InMemoryCache for RuntimeCache consistency#14751

[functions] use JSON serialization in InMemoryCache for RuntimeCache consistency#14751
kldavis4 merged 3 commits intomainfrom
kd/01-27-_functions_use_json_serialization_in_inmemorycache_for_runtimecache_consistency

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kldavis4 commented Jan 27, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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TL;DR

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kldavis4 commented Jan 27, 2026 •

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