How to Custom Build Lodash Using lodash-cli

Custom building the Lodash library allows developers to significantly reduce JavaScript bundle sizes by including only the specific utility functions required for a project. This article explains how to install the lodash-cli utility, generate tailored Lodash builds using various CLI arguments such as include and category, specify export formats, and integrate the compilation step into your build workflow.

1. Prerequisites and Installation

To use lodash-cli, you need Node.js and npm installed on your machine. You can install the tool globally:

npm install -g lodash-cli

Alternatively, you can run it directly without a permanent global installation using npx:

npx lodash-cli <arguments>

2. Basic Custom Builds

By default, running lodash generates the full library. To generate a build containing only specific functions, use the include flag followed by a comma-separated list of function names (without spaces).

lodash include="map,filter,debounce,throttle"

This command creates a lodash.custom.min.js file in your current working directory, including only the specified functions and their internal dependencies.

3. Using Categories

Lodash categorizes its methods into functional groups such as collection, array, object, and string. You can include entire categories using the category flag:

lodash category="collection,object"

You can also combine categories with specific functions:

lodash category="array" include="debounce,throttle"

4. Excluding Methods

If you need most of a category or build but want to omit certain heavy or unused methods, use the minus flag:

lodash category="collection" minus="shuffle,sample"

5. Specifying Output Formats and Targets

You can configure output formats, environments, and file destinations using additional flags:

Export Formats: Use the exports flag to define module definitions (es, amd, commonjs, node, or global).
```
lodash include="cloneDeep,isEmpty" exports="es"
```
Output Path: Use the -o or --output flag to save the file to a specific path and name.
```
lodash include="get,set" -o "./src/vendor/lodash.custom.js"
```
Development Build: By default, Lodash builds are minified. Add the development modifier to output an unminified, readable version.
```
lodash development include="chunk,compact"
```

6. Automating via package.json

To ensure consistency across development environments, add your custom build command to your project's package.json scripts:

{
  "scripts": {
    "build:lodash": "lodash include=\"debounce,throttle,get,set\" exports=\"es\" -o \"./src/utils/lodash.custom.js\""
  },
  "devDependencies": {
    "lodash-cli": "^4.17.5"
  }
}

Running npm run build:lodash will regenerate the custom bundle whenever your dependencies or utility requirements change.