Lodash Internal `baseFindIndex` Module (v3.6.0)

3.6.0 · abandoned · verified Sun Apr 19

This package, `lodash._basefindindex`, provides a standalone CommonJS module for the internal `baseFindIndex` function from Lodash version 3.6.0. This function is an integral part of Lodash's core, designed to find the index of an element within a collection using a predicate, without directly exposing it as a public API method. In its original context, such modular builds allowed for more granular imports and smaller bundle sizes before widespread adoption of ES Modules and advanced tree-shaking capabilities. However, the main Lodash library is now at version 4.18.1, with its v3.x line officially reaching end-of-life in January 2016. Consequently, `lodash._basefindindex` (v3.6.0) is considered an abandoned, legacy package, and its use is generally discouraged in modern JavaScript development in favor of the full `lodash` or `lodash-es` packages, which benefit from active maintenance and regular security updates.

Common errors

```
TypeError: baseFindIndex is not a function
```
cause Attempting to use ES module `import` syntax (e.g., `import baseFindIndex from 'lodash._basefindindex'`) instead of CommonJS `require()` for this v3.x package.

fix Change the import statement to `const baseFindIndex = require('lodash._basefindindex');`.
```
ReferenceError: require is not defined
```
cause Trying to use `require()` in an ES module context without proper transpilation or configuration, or directly in a browser without a CommonJS loader.

fix Ensure your environment supports CommonJS modules (e.g., Node.js) or use a bundler (like Webpack or Rollup) configured for CommonJS. Alternatively, switch to `lodash-es` for ES module compatibility.
```
TypeError: Cannot read properties of undefined (reading 'length')
```
cause Incorrect arguments passed to `baseFindIndex`, such as `array` being `undefined` or `null`, or the predicate function not being callable, which can happen if you incorrectly assume v4 behavior with this v3 module.

fix Carefully review the function signature and expected argument types for `lodash._basefindindex` (v3.x) and ensure the inputs are valid. Refer to the Lodash v3 documentation for precise API details.

Warnings

breaking This `lodash._basefindindex` package is derived from Lodash v3.6.0. The v3.x line officially reached End-of-Life (EOL) in January 2016. It is no longer actively maintained for bug fixes, performance improvements, or security updates.
Fix: Migrate to the main `lodash` package (v4.18.1 or newer) or `lodash-es` for modern usage. Use `_.findIndex` or `_.findLastIndex`.
breaking Using this v3.x internal module alongside modern Lodash (v4+) may lead to compatibility issues, unexpected behavior, or performance regressions due to internal API changes between major versions.
Fix: Avoid mixing different major versions of Lodash components. Upgrade all Lodash-related dependencies to v4+.
gotcha This package exports a CommonJS module and does not natively support ES module `import` syntax. Attempting to use `import baseFindIndex from 'lodash._basefindindex'` will result in runtime errors.
Fix: Always use `require()` for this specific package: `const baseFindIndex = require('lodash._basefindindex');`.
gotcha Modern JavaScript bundlers with tree-shaking capabilities (e.g., Webpack, Rollup) can effectively optimize `lodash-es` imports, making these granular, pre-ESM internal modules obsolete and potentially counterproductive for bundle size optimization.
Fix: For smaller bundle sizes with modern tooling, use `lodash-es` and import specific methods: `import { findIndex } from 'lodash-es';`.

Install

npm install lodash._basefindindex npm
yarn add lodash._basefindindex yarn
pnpm add lodash._basefindindex pnpm

Imports

baseFindIndex
wrong:
```
import baseFindIndex from 'lodash._basefindindex';
```
correct:
```
const baseFindIndex = require('lodash._basefindindex');
```
This package is a CommonJS module from Lodash v3.x and does not support ES module `import` syntax. For modern applications, use `_.findIndex` from the main `lodash` package or `lodash-es`.
findIndex (modern equivalent)
wrong:
```
const { findIndex } = require('lodash._basefindindex');
```
correct:
```
import { findIndex } from 'lodash-es';
// OR
import findIndex from 'lodash/findIndex';
```
The public equivalent `_.findIndex` should be imported from `lodash-es` for tree-shaking or directly from `lodash/findIndex` for CommonJS builds in modern Lodash (v4+). This `_basefindIndex` module is an internal function from v3.x.
lodash (main library)
wrong:
```
const { _basefindIndex } = require('lodash');
```
correct:
```
const _ = require('lodash');
_.findIndex(array, predicate);
```
The internal `_basefindIndex` is not directly exposed on the main `_` object. Use the public `_.findIndex` method instead.

Quickstart

Demonstrates how to import and use the `baseFindIndex` function from this legacy module. It also contrasts it with the equivalent public API usage in modern Lodash.

const baseFindIndex = require('lodash._basefindindex');

const users = [
  { 'user': 'barney', 'active': false },
  { 'user': 'fred',   'active': false },
  { 'user': 'pebbles', 'active': true }
];

// Find the index of the first active user
const predicate = (o) => o.active;
const index = baseFindIndex(users, predicate, 0, false);

console.log(`Index of first active user: ${index}`);

// Example of how you would use the modern public API (not this package)
const _ = require('lodash');
const modernIndex = _.findIndex(users, predicate);
console.log(`Index using modern _.findIndex: ${modernIndex}`);

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