lodash.restparam

Common errors

• TypeError: _.restParam is not a function

  cause You are likely trying to use `_.restParam` with a version of Lodash v4.0.0 or higher where the function was renamed to `_.rest`.
  fix Update your code to use `_.rest` instead of `_.restParam`, or use native JavaScript rest parameters (`...args`). If you are directly importing `lodash.restparam`, ensure your project does not implicitly rely on a newer version of Lodash.

• Bundle size unexpectedly large despite only using a few Lodash functions.

  cause Modular `lodash.*` packages like `lodash.restparam` bundle their internal dependencies. If multiple such packages are used, or if the main `lodash` package is also present, it can lead to duplicated code in your final bundle, circumventing potential tree-shaking benefits.
  fix Replace `lodash.restparam` with native JavaScript rest parameters (`...args`). For other Lodash functions, prefer importing specific methods directly from the main `lodash` package (e.g., `import { someMethod } from 'lodash';`) and leverage modern bundlers for tree-shaking, or use `babel-plugin-lodash`.

Warnings

• breaking The `_.restParam` function was renamed to `_.rest` in Lodash v4.0.0. This `lodash.restparam` package is locked at version 3.x, meaning it will not provide the updated function name or any features from Lodash v4+.
  Fix: Use `_.rest` from the main `lodash` package or, preferably, native JavaScript rest parameters (`...args`). If you must use `_.restParam`, stick to Lodash v3.x or this specific modular package.
• deprecated All individual, per-method `lodash.*` packages (like `lodash.restparam`) are officially discouraged by the Lodash team and are scheduled for removal in Lodash v5. They often lead to larger bundle sizes compared to importing specific functions from the main `lodash` package.
  Fix: Migrate to using native JavaScript rest parameters (`...args`) or import `_.rest` directly from the main `lodash` package (e.g., `import { rest } from 'lodash';`). Lodash provides a `jscodeshift` transform to assist with this migration.
• gotcha Native JavaScript introduced rest parameters (`...args`) in ES6 (ES2015), providing equivalent functionality to `_.restParam` and `_.rest`. Using this `lodash.restparam` package often introduces unnecessary dependency and bundle size.
  Fix: Favor native JavaScript rest parameters (`function foo(arg1, ...restArgs)`) over `lodash.restparam`. This reduces bundle size and avoids external dependencies for a standard language feature.
• gotcha As an unmaintained, older modular package, `lodash.restparam` will not receive security updates. The main `lodash` package has had security advisories (e.g., prototype pollution fixes in v4.18.0) which would not be patched in this specific module.
  Fix: Discontinue use of this package and migrate to native JavaScript rest parameters or the `_.rest` function from the actively maintained `lodash` main package.

Install

• npm install lodash.restparam npm
• yarn add lodash.restparam yarn
• pnpm add lodash.restparam pnpm

Imports

• restParam
  wrong:

  import { restParam } from 'lodash.restparam';

  correct:

  import restParam from 'lodash.restparam';

  This package is an old, unmaintained CommonJS module, but bundlers often provide ESM interoperability. Named imports are incorrect for this module's export style.
• restParam (CommonJS)

  const restParam = require('lodash.restparam');

  This is the documented and intended way to import this module.
• Rest parameter (modern Lodash)
  wrong:

  import { restParam } from 'lodash';

  correct:

  import { rest } from 'lodash';

  In modern Lodash (v4+), the function is named `rest`, not `restParam`. The dedicated `lodash.restparam` package is deprecated; prefer importing `rest` from the main `lodash` package or using native rest parameters.

Quickstart

Demonstrates the usage of `lodash.restparam` to create a function that handles a variable number of arguments, alongside its modern native JavaScript equivalent.

import restParam from 'lodash.restparam';

const greetWithManyNames = restParam(function(greeting, ...names) {
  return `${greeting} ${names.join(', ')}!`;
}, 1); // Collect all arguments from index 1 (the second argument) onwards

console.log(greetWithManyNames('Hello', 'Alice', 'Bob', 'Charlie'));
// Expected output: "Hello Alice, Bob, Charlie!"

// Demonstrating the equivalent with native rest parameters, preferred in modern JS:
function modernGreet(greeting, ...names) {
  return `${greeting} ${names.join(', ')}!`;
}
console.log(modernGreet('Hi', 'David', 'Eve'));
// Expected output: "Hi David, Eve!"