nodejs-polars

library0.24.1jsnpmunverified

nodejs-polars is a Node.js binding for the Polars DataFrame library, built on Rust for performance. Version 0.24.1 requires Node >= 20, ships TypeScript types, and supports ESM and CJS. It provides fast data manipulation via lazy and eager APIs, with features like groupby, join, sort, and window functions. Key differentiators: significantly faster than pandas, lower memory usage, and a more expressive API. Released frequently (weekly/monthly), tracking the Rust core.

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npm install nodejs-polars

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INSTALL

IMPORT

SIG · NODEJS-POLARS

nodejs-polars

databasejavascriptv0.24.1

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.

✓ import pl from 'nodejs-polars'

✗ const pl = require('nodejs-polars')

Both ESM and CJS supported. ESM is recommended for Node >= 20.

DataFrame

✓ import { DataFrame } from 'nodejs-polars'

✗ const { DataFrame } = require('nodejs-polars')

Named export for TypeScript type usage.

Series

✓ import { Series } from 'nodejs-polars'

Named export for TypeScript type usage.

Demonstrates creating a DataFrame, filtering, grouping, and the lazy API with collect.

import pl from 'nodejs-polars'; // Create a DataFrame const df = pl.DataFrame({ name: ["Alice", "Bob", "Charlie"], age: [25, 30, 35], city: ["New York", "London", "Paris"] }); // Perform operations const filtered = df.filter(pl.col("age").gt(25)); const aggregated = df.groupBy("city").agg(pl.col("age").mean()); console.log(filtered); console.log(aggregated); // Lazy API const lf = df.lazy() .filter(pl.col("age").gt(25)) .select(["name", "age"]); const result = await lf.collect(); console.log(result);

Debug

Known issues

gotchaDefault import uses `import pl from 'nodejs-polars'`, not named imports.

fix

Use default import for the main pl object.

affects: *

breakingVersion 0.14.0 changed the lazy API to require async `collect()`.

fix

Use `await lf.collect()` and ensure calling context is async.

affects: >=0.14.0

deprecatedSome function parameters have been renamed; e.g., `sort(descending: true)` changed to `sort({ descending: true })`.

fix

Pass arguments as a configuration object instead of positional booleans.

affects: >=0.18.0

gotchaSeries indices are zero-based but normal array indexing works; negative indexing is not supported.

fix

Use `.get(idx)` for negative indices or slice.

affects: *

breakingMinimum Node.js version is now 20; older versions are not supported.

fix

Upgrade to Node.js >=20.

affects: >=0.24.0

deprecated`pl.lit()` is used for literal values; there's no alternative at this time.

fix

Continue using `pl.lit()` as it's still current.

affects: *

Errors

Common errors & fixes

Error: Must use import to load ES Module: /path/to/node_modules/nodejs-polars/lib/index.js

Using `require()` on an ESM-only module.

fix

Use `import pl from 'nodejs-polars'` in your code, or ensure your Node.js version supports ESM and add `"type": "module"` to your package.json.

TypeError: pl.DataFrame is not a constructor

Attempting to import named export 'DataFrame' from default import pl. Actually, pl.DataFrame is a method, not a class constructor in older versions.

fix

Use `pl.DataFrame({...})` directly for constructing DataFrames.

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

Incorrect usage of lazy API: `collect` is not called or called synchronously.

fix

Use `await lf.collect()` and ensure the surrounding function is async.

Upgrade

Version history

0.24.1latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

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Resources

githubhttps://github.com/pola-rs/nodejs-polars ↗

packagenodejs-polars ↗

homepagehttps://github.com/pola-rs/nodejs-polars#readme ↗