util

What is util?

The 'util' package is a core Node.js module that provides utilities for programmatic use in JavaScript. It includes a collection of helper functions for various tasks such as formatting strings, inspecting objects, and using inheritance.

What are util's main functionalities?

format

Formats a string using placeholders and returns it. Similar to printf in C.

const util = require('util');
console.log(util.format('%s:%s', 'foo', 'bar', 'baz')); // 'foo:bar baz'

inspect

Returns a string representation of an object for debugging purposes, with options to show hidden properties and control the depth of inspection.

const util = require('util');
console.log(util.inspect({ foo: 'bar' }, { showHidden: false, depth: null }));

inherits

Allows one constructor to inherit the prototype methods from another, a utility for implementing object-oriented inheritance.

const util = require('util');
function Base() {}
function Derived() {}
util.inherits(Derived, Base);

promisify

Converts a callback-based function to a function that returns a promise, facilitating the use of async/await.

const util = require('util');
const fs = require('fs');
const readFileAsync = util.promisify(fs.readFile);
readFileAsync('example.txt', 'utf8').then(console.log).catch(console.error);

Other packages similar to util

lodash

Lodash is a utility library offering a wide range of methods for manipulating objects, arrays, strings, etc. It's more comprehensive than 'util' but doesn't include some of the Node.js-specific utilities like promisify.

underscore

Underscore.js is a utility library similar to Lodash, providing functional programming helpers without extending any built-in objects. It's less feature-rich compared to Lodash and doesn't include Node.js-specific utilities.

chalk

Chalk is a library for styling terminal strings. It doesn't offer the broad utility functions of 'util' but focuses on a specific area of string styling which 'util' doesn't cover.

bluebird

Bluebird is a library focused on providing advanced features for promises, such as cancellation, progress, and long stack traces. It complements 'util' by enhancing promise functionality beyond what 'util.promisify' offers.

README

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