Registry / devops / babel-plugin-pure-calls-annotation

babel-plugin-pure-calls-annotation

library0.4.2jsnpmunverified

A Babel plugin (v0.4.2, stable, low release cadence) that automatically adds /*#__PURE__*/ comments to call expressions in variable declarators, assignment expressions, call arguments, and other expression contexts. This helps bundlers like Webpack identify side-effect-free calls for tree shaking and dead code elimination. Unlike manual annotation, it eliminates human error and ensures consistent coverage across large codebases. Ships TypeScript types and integrates seamlessly into any Babel-based build pipeline.

devops

npm install babel-plugin-pure-calls-annotation

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-PURE-

babel-plugin-pure-calls-annotation

devopsjavascriptv0.4.2

Install

—

Import

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Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

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

default

✓ import pureCallsAnnotation from 'babel-plugin-pure-calls-annotation'

✗ const pureCallsAnnotation = require('babel-plugin-pure-calls-annotation')

Default import works in ESM; CommonJS require is also supported but discouraged for TypeScript

pureCallsAnnotation

✓ import pureCallsAnnotation from 'babel-plugin-pure-calls-annotation'

Plugin is used as a Babel plugin, imported as default and passed to plugins array

BabelPluginPureCallsAnnotation

✓ import BabelPluginPureCallsAnnotation from 'babel-plugin-pure-calls-annotation'

✗ const { BabelPluginPureCallsAnnotation } = require('babel-plugin-pure-calls-annotation')

Named export does not exist; only default export. Use default import.

Add the plugin to Babel config to automatically annotate pure call expressions with /*#__PURE__*/ for tree shaking.

// babel.config.js module.exports = { plugins: [ 'babel-plugin-pure-calls-annotation' ] }; // Input: const result = compute() // Output: const result = /*#__PURE__*/compute()

Debug

Known issues

gotchaThe plugin annotates all eligible call expressions, including those that may have side effects. Use with caution; only include if you are certain the annotated calls are pure.

fix

Manually verify or use other methods (e.g., /*#__PURE__*/ comments) to ensure purity.

affects: *

breakingBREAKING: Version 0.4.0 changed annotation behavior for IIFEs: previously IIFEs were not annotated; now they are.

fix

If you rely on IIFEs not being annotated, downgrade to <0.4.0 or update your code to handle the change.

affects: >=0.4.0

deprecatedThe plugin may not be actively maintained; last release was in 2021. Consider alternatives like manual annotation or custom Babel plugin for tree shaking.

fix

Review current tree shaking needs; use terser-webpack-plugin with sideEffects: false as a more maintained alternative.

affects: *

gotchaDoes not annotate call expressions in all positions (e.g., as standalone statements). Only variable declarators, assignment expressions, and call arguments are covered.

fix

Manually add /*#__PURE__*/ to unannotated pure calls or extend the plugin.

affects: *

Errors

Common errors & fixes

SyntaxError: 'babel-plugin-pure-calls-annotation' threw an error: Cannot find module '@babel/core'

Missing @babel/core as a peer dependency.

fix

npm install @babel/core --save-dev

TypeError: Cannot read properties of undefined (reading 'callee')

The plugin expects a Babel AST node with a callee property; corrupted or outdated Babel version may cause this.

fix

Update Babel to version 7.x or above and ensure the plugin is compatible.

Error: Plugin/preset files are not allowed to export objects, only functions.

This error occurs if the plugin is imported incorrectly (e.g., using named import instead of default).

fix

Use default import: import pureCallsAnnotation from 'babel-plugin-pure-calls-annotation'

Upgrade

Version history

0.4.2latest on npm

Audit

Dependencies

@babel/corerequiredPeer dependency; plugin requires Babel core for transformation

Agent activity

5 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/morlay/babel-plugin-pure-calls-annotation ↗

packagehttps://www.npmjs.com/package/babel-plugin-pure-calls-annotation ↗