Advanced Topics

Customizing Lodash

Lodash allows you to create custom builds to include only the methods you need, which can help minimize your bundle size.

• Creating a Custom Build:
  1. Clone the Repository:

git clone https://github.com/lodash/lodash.git

• Install Dependencies:

cd lodash npm install

• Build Your Custom Version: Use the lodash-cli to create a custom build. You can specify which functions to include.

npx lodash include=chunk,debounce,map

• Use the Custom Build: The custom build will be in the lodash-custom directory. Include this build in your project.

Lazy Evaluation

Lodash provides lazy evaluation with _.chain() for efficient processing of large datasets.

• Example:

const data = _.range(1, 10000); const result = _.chain(data) .filter(n => n % 2 === 0) .map(n => n * n) .take(10) .value(); // Processes data lazily and retrieves only the first 10 results

Immutable Data Structures

Lodash’s utilities are not inherently immutable, but you can use them in conjunction with immutable data libraries like Immutable.js or Immer.

• Using Immer with Lodash:

import produce from 'immer'; import _ from 'lodash'; const state = { user: { name: 'John', age: 25 }, items: [1, 2, 3] }; const nextState = produce(state, draft => { _.set(draft, 'user.age', 26); draft.items = _.concat(draft.items, 4); }); // nextState: { user: { name: 'John', age: 26 }, items: [1, 2, 3, 4] }