flaglint

library0.6.0jsnpmunverified

FlagLint (v0.6.0) is a CLI tool that scans LaunchDarkly Node.js SDK usage and generates safe, reviewable migration diffs to OpenFeature. It inventories all direct calls (boolVariation, stringVariation, etc.), reports dynamic keys and unguarded patterns, and provides a CI gate to prevent new vendor-coupled flag access. Released under MIT, it supports both ESM and CJS imports from launchdarkly-node-server-sdk and @launchdarkly/node-server-sdk. Key differentiators: argument-order error detection, automated migration with --apply, and zero-runtime dependencies (only Node >=20 required).

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npm install flaglint

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INSTALL

IMPORT

SIG · FLAGLINT

flaglint

devopsjavascriptv0.6.0

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.

FlagLint

✓ import { FlagLint } from 'flaglint'

✗ const FlagLint = require('flaglint')

ESM-only; FlagLint is the default export used programmatically, but typical usage is via npx CLI.

CLI (npx)

✓ npx flaglint scan ./src

✗ npx flaglint --scan ./src

CLI commands are subcommands (scan, migrate, audit, validate), not flags.

scan result (programmatic)

✓ import { scan } from 'flaglint'; const result = await scan('./src');

✗ const { scan } = require('flaglint'); const result = scan('./src');

scan is an async named export; CJS require() breaks as of v0.6.0.

Complete workflow: scan LaunchDarkly usage, preview migration diff, apply rewrite, and enforce no-direct-calls in CI.

// Step 1: Scan a project for LaunchDarkly SDK calls npx flaglint scan ./src // Step 2: Preview the migration diff npx flaglint migrate ./src --dry-run // Step 3: Apply migration (only guarded calls) npx flaglint migrate ./src --apply // Step 4: Add CI gate to prevent new direct calls npx flaglint validate --no-direct-launchdarkly ./src echo 'Exit code reflects pass/fail.'

Debug

Known issues

breakingv0.6.0 drops support for Node <20. Update engines if using older Node versions.

fix

Upgrade to Node >=20.

affects: >=0.6.0

deprecatedCJS require() is not supported; only ESM imports work.

fix

Use import syntax or npx CLI.

affects: >=0.6.0

gotchaMigration --apply rewrites only statically explicit calls. Dynamic keys, detail methods, and bulk calls are reported but not auto-fixed.

fix

Review dynamic-key calls manually; use --dry-run first.

affects: >=0.0.0

gotchaThe tool does not handle LaunchDarkly client initialization or OpenFeature provider setup—you must add provider setup scaffolding manually.

fix

Follow the inline guidance in the migration diff or read the docs for provider setup.

affects: >=0.0.0

gotchaFlagLint only supports server-side LaunchDarkly Node SDKs (launchdarkly-node-server-sdk, @launchdarkly/node-server-sdk). Client-side/mobile SDKs are not supported.

fix

Use a different migration strategy for client-side SDKs.

affects: >=0.0.0

Errors

Common errors & fixes

Error: Cannot find module 'flaglint'

Trying to require('flaglint') in a CommonJS environment.

fix

Use ESM: add "type": "module" in package.json or use .mjs extension. Or use npx flaglint.

TypeError: scan is not a function

Importing { scan } from 'flaglint' incorrectly when using default export.

fix

Use import { scan } from 'flaglint' or import FlagLint from 'flaglint' and call new FlagLint().scan().

flaglint: command not found

Running npx incorrectly or package not installed globally.

fix

Use npx flaglint (without install) or install globally with npm i -g flaglint.

Upgrade

Version history

0.6.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

25 hits · last 30 days

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Resources

githubhttps://github.com/flaglint/flaglint ↗

packageflaglint ↗

homepagehttps://flaglint.dev ↗