fix: patch undici File support on Node.js < 20 #588

akitaSummer · 2025-08-06T07:57:17Z

Summary by CodeRabbit

New Features
- Improved compatibility for certain environments by adding polyfills for file handling and Unicode string methods.
- Enhanced string handling with new methods for checking and converting to well-formed Unicode strings.
Style
- Minor formatting adjustment for improved code readability (no impact on functionality).
Bug Fixes
- Disabled a specific test assertion related to multipart/form-data header validation to prevent false test failures.
Chores
- Added ESLint rule to warn when native objects are extended, promoting better code practices.

coderabbitai · 2025-08-06T07:57:26Z

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📥 Commits

Reviewing files that changed from the base of the PR and between 89fbcb3 and a6a9240.

📒 Files selected for processing (10)

.eslintrc (1 hunks)
src/HttpClient.ts (1 hunks)
src/index.ts (1 hunks)
src/utils.ts (2 hunks)
test/HttpClient.test.ts (1 hunks)
test/diagnostics_channel.test.ts (2 hunks)
test/fixtures/server.ts (2 hunks)
test/options.stream.test.ts (1 hunks)
test/options.timeout.test.ts (1 hunks)
test/urllib.options.rejectUnauthorized-false.test.ts (2 hunks)

Walkthrough

A blank line was added in src/index.ts for readability. In src/utils.ts, the patchForNode16 function was updated to polyfill the global File object and add toWellFormed and isWellFormed methods to String.prototype if they are missing, enhancing compatibility with Node.js 16. The ESLint configuration was updated to warn on extending native objects. A test assertion checking multipart boundary format was commented out.

Changes

Cohort / File(s)	Change Summary
Formatting adjustment `src/index.ts`	Added a blank line after the `patchForNode16` import and before its invocation; no functional changes.
Node.js 16 polyfills and string methods `src/utils.ts`	Updated `patchForNode16` to polyfill global `File` and add `String.prototype.toWellFormed` and `isWellFormed` if missing, using Node.js utilities.
ESLint configuration update `.eslintrc`	Added `"no-extend-native": "warn"` rule to ESLint configuration to warn on extending native objects.
Test adjustment `test/options.stream.test.ts`	Commented out an assertion that checked the `content-type` header for multipart boundary format in a formstream upload test.

Sequence Diagram(s)

sequenceDiagram
    participant App
    participant patchForNode16
    participant globalThis
    participant StringPrototype

    App->>patchForNode16: Call patchForNode16()
    patchForNode16->>globalThis: Check if File exists
    alt File missing
        patchForNode16->>globalThis: Assign File polyfill
    end
    patchForNode16->>StringPrototype: Check for toWellFormed and isWellFormed
    alt Methods missing
        patchForNode16->>StringPrototype: Add toWellFormed and isWellFormed polyfills
    end

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~7 minutes

Possibly related PRs

fix: support use on Node.js 16 #550: Introduces the initial patchForNode16 function with polyfills for ReadableStream, Blob, and DOMException—both PRs enhance Node.js 16 compatibility in src/utils.ts.
fix: patch TransformStream on Node.js 16 #564: Adds a polyfill for TransformStream in patchForNode16; both PRs update the same function to support missing globals in Node.js 16.
test: add node 16 #562: Adds Node.js 16 to the CI test matrix and conditionally skips tests on Node.js 16; related by focus on Node.js 16 support but modifies different code areas.

Suggested labels

enhancement

Poem

In Node.js sixteen, some features are shy,
So rabbits patch in File, let well-formed strings fly.
With polyfills hopping, the globals align,
Each method in place, the code runs just fine.
A hop, a fix, a Unicode cheer—
Node’s quirks are tamed, the bugs disappear! 🐇✨

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Commit unit tests in branch fix/undici

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gemini-code-assist

Summary of Changes

Hello @akitaSummer, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

I've implemented a fix primarily focused on enhancing compatibility for undici and other web-standard APIs in older Node.js environments. This involves ensuring that the File global object is available and polyfilling modern String.prototype methods like toWellFormed and isWellFormed. The goal is to provide a more robust and consistent environment for applications relying on these features, especially when running on Node.js versions prior to 20.

Highlights

Ensuring globalThis.File availability for undici compatibility: I've added a check within the patchForNode16 function to ensure that globalThis.File is defined. If it's missing, I assign the File class imported from node:buffer to it. This change is specifically aimed at resolving compatibility issues with undici when running on Node.js versions older than 20, as indicated by the linked undici GitHub issue.
Polyfilling String.prototype.toWellFormed and String.prototype.isWellFormed: I've also included polyfills for String.prototype.toWellFormed and String.prototype.isWellFormed within the patchForNode16 function. These polyfills use toUSVString from node:util to provide the functionality of these modern string methods, which are useful for handling well-formed Unicode strings.

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gemini-code-assist

Code Review

This pull request adds polyfills for File, String.prototype.toWellFormed, and String.prototype.isWellFormed to improve compatibility with different Node.js versions and undici library versions. The changes are generally good, but I've suggested a refactoring for the string prototype polyfills to improve code clarity, fix inconsistent indentation, and reduce the number of @ts-ignore suppressions.

src/utils.ts

coderabbitai

Actionable comments posted: 2

📜 Review details

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 9e62fb1 and 2f943f8.

📒 Files selected for processing (2)

src/index.ts (1 hunks)
src/utils.ts (2 hunks)

🧰 Additional context used

🪛 GitHub Check: Node.js / Test (ubuntu-latest, 20)

src/utils.ts

[failure] 251-251:
Expected indentation of 4 spaces but found 6

[failure] 250-250:
Expected indentation of 6 spaces but found 10

[failure] 249-249:
Expected indentation of 6 spaces but found 10

[failure] 248-248:
Expected indentation of 6 spaces but found 10

[failure] 247-247:
Unexpected space before function parentheses

[failure] 247-247:
String prototype is read only, properties should not be added

[failure] 247-247:
Expected indentation of 4 spaces but found 6

[failure] 246-246:
Expected indentation of 4 spaces but found 6

[failure] 245-245:
Expected indentation of 4 spaces but found 6

[failure] 241-241:
Trailing spaces not allowed

🪛 GitHub Check: Node.js / Test (ubuntu-latest, 18)