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

babel-plugin-annotate-pure-calls

library0.5.0jsnpmunverified

Babel plugin (v0.5.0) that automatically inserts #__PURE__ annotations on top-level call expressions and new expressions in assignment contexts, enabling UglifyJS and Terser to perform dead code elimination for improved bundle sizes. Targeted at libraries where top-level calls are generally side-effect-free, but may break code if misapplied. Current stable version is 0.5.0 with Node >= 18 and peer dependency on @babel/core ^7.0.0. The plugin is actively maintained but the API is simple and stable. Compared to alternatives like 'annotate-pure-call-in-variable-declarator', this plugin covers broader contexts (IIFEs, nested IIFEs) and is more widely adopted.

devops

npm install babel-plugin-annotate-pure-calls

github ↗package ↗

INSTALL

IMPORT

SIG · BABEL-PLUGIN-ANNOT

babel-plugin-annotate-pure-calls

devopsjavascriptv0.5.0

Install

—

Import

—

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.

plugin

✓ // In .babelrc or babel.config.js: plugins: ['annotate-pure-calls']

✗ plugins: ['babel-plugin-annotate-pure-calls']

The plugin name is 'annotate-pure-calls' when used in Babel config; the full npm package name is optional.

default

✓ const annotatePureCalls = require('babel-plugin-annotate-pure-calls');

✗ import annotatePureCalls from 'babel-plugin-annotate-pure-calls';

The plugin is exported as CommonJS; ES import may not work depending on bundler configuration.

annotate-pure-calls

✓ // programmatic usage: const babel = require('@babel/core'); babel.transform(code, { plugins: [require('babel-plugin-annotate-pure-calls')] });

✗ babel.transform(code, { plugins: ['annotate-pure-calls'] });

When using programmatic API, you must pass the plugin object, not a string. Strings only work in config files.

Shows installation, configuration, and a simple example of the plugin annotating a pure call.

// Install: npm install --save-dev babel-plugin-annotate-pure-calls // .babelrc { "plugins": ["annotate-pure-calls"] } // Input: top-level call var inc = add(1); // Output: annotated with #__PURE__ var inc = /*#__PURE__*/add(1); // Note: Only top-level calls in assignment contexts are annotated; calls like mutate({}) remain unannotated.

Debug

Known issues

gotchaPlugin may annotate impure top-level calls (e.g., calls with side effects) as pure, leading to broken code after minification.

fix

Use only for libraries where top-level calls are predominantly side-effect-free; manually review or use additional linting.

affects: all

gotchaCalls not in an assignment context (e.g., pure statements like mutate({})) are NOT annotated, which is correct but may be surprising for those expecting all top-level calls to be annotated.

fix

Understand the plugin's scope: only variable declarations and assignment expressions at top level are annotated.

affects: all

gotchaThe plugin requires Node >= 18 as of version 0.5.0; older versions may not work.

fix

Upgrade Node to version 18 or later, or use an older version of the plugin (if available).

affects: >=0.5.0

Errors

Common errors & fixes

Cannot find module 'babel-plugin-annotate-pure-calls'

Plugin not installed or installed globally instead of locally.

fix

Run npm install --save-dev babel-plugin-annotate-pure-calls in the project directory.

Unmet peer dependency @babel/core@^7.0.0

Missing or incompatible version of @babel/core.

fix

Install @babel/core: npm install --save-dev @babel/core (ensure version ^7.0.0).

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

Plugin is not a function; imported incorrectly when using programmatic API.

fix

Use require('babel-plugin-annotate-pure-calls') instead of a string in Babel transform options.

Upgrade

Version history

0.5.0latest on npm

Audit

Dependencies

@babel/corerequiredThe plugin is a Babel transform and requires @babel/core to function as a plugin.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/Andarist/babel-plugin-annotate-pure-calls ↗

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