Require vs. Import — What's the Difference?

By Tayyaba Rehman & Maham Liaqat — Updated on May 14, 2024

"Require" is used to include modules in Node.js, maintaining state between calls, whereas "Import" allows static and dynamic imports in ES6+ JavaScript modules.

Require vs. Import — What's the Difference?

Difference Between Require and Import

Key Differences

"Require" is a function in Node.js that reads and executes JavaScript files, making module contents available within another file. "Import," on the other hand, is part of ECMAScript 6 (ES6) and provides a more flexible way to load modules asynchronously or statically.

When using "require," the module system caches the exports after the first load, which can enhance performance in subsequent calls. In contrast, "import" allows for more dynamic dependency resolution and can benefit from static analysis tools and tree-shaking to eliminate unused code.

The syntax for "require" is simpler, as it takes the module path as an argument and returns the module’s exports. "Import," whereas, offers a variety of syntax options including named imports, default imports, and namespace imports, which can make it more versatile.

"Require" does not support the asynchronous loading of modules directly and blocks the execution while files are being read. "Import" provides the means to dynamically load modules using the 'import()' expression, which returns a promise.

In terms of scope, variables declared in modules loaded via "require" are private to that module by default. "Import" also encapsulates its modules, but it explicitly requires exports and imports to be defined, which can make sharing across modules clearer and more structured.

Comparison Chart

Introduced in

CommonJS, used in Node.js

ECMAScript 6 (ES6)

Syntax Simplicity

Simple function call

Offers various syntaxes for flexibility

Caching

Caches modules on first load

Depends on the module loader

Dynamic Loading

Not supported natively

Supports dynamic imports with promises

Execution

Synchronous, blocks execution

Can import asynchronously

Compare with Definitions

Require

Used primarily in Node.js environments.

Const http = require('http');

Import

A statement to load ES6 modules, both synchronously and asynchronously.

Import { readFile } from 'fs/promises';

Require

Caches the module on first load, enhancing performance.

Const _ = require('lodash'); // Cached after first load

Import

Allows selective loading of module components.

Import { Component } from 'react';

Require

A function to include JavaScript modules available locally or installed via npm.

Const fs = require('fs');

Import

Can dynamically import modules using promises.

Import('path/to/module').then(module => {...});

Require

Directly assigns the exported module to a variable.

Const express = require('express');

Import

Supports tree shaking to eliminate unused code.

Import { useEffect } from 'react';

Require

To have as a requisite or necessity; need or depend on

Do you require assistance? Most plants require plenty of water.

Import

An import in the receiving country is an export from the sending country. Importation and exportation are the defining financial transactions of international trade.In international trade, the importation and exportation of goods are limited by import quotas and mandates from the customs authority.

Require

To stipulate as obligatory by authority

The law requires full disclosure of charitable donations.

Import

To bring or carry in from an outside source, especially to bring in (goods or materials) from a foreign country for trade or sale.

Require

To demand as obligatory or appropriate

Skiing requires practice.

Import

(Computers) To receive (data) into one program from another.

Require

To impose an obligation on; compel

The school requires all students to study mathematics.

Import

To carry or hold the meaning of; signify

Had trouble understanding what the strange word imported.

Require

(obsolete) To ask (someone) for something; to request.

Import

To express or make known

The news imported by their letter.

Require

To demand, to insist upon (having); to call for authoritatively.

Import

To betoken or indicate

A high inflation rate importing hard times for the consumer.

Require

Naturally to demand (something) as indispensable; to need, to call for as necessary.

Import

Something imported

Levied a tax on imports from overseas.

Require

To demand of (someone) to do something.

Import

The act or occupation of importing goods or materials.

Require

To demand; to insist upon having; to claim as by right and authority; to exact; as, to require the surrender of property.

Shall I say to CæsarWhat you require of him?

By nature did what was by law required.

Import

Meaning; signification

The import of his statement is ambiguous.

Require

To demand or exact as indispensable; to need.

Just gave what life required, and gave no more.

The two last [biographies] require to be particularly noticed.

Import

Importance; significance

A legal decision of far-reaching import.

Require

To ask as a favor; to request.

I was ashamed to require of the king a band of soldiers and horsemen to help us against the enemy in the way.

Import

(countable) Something brought in from an exterior source, especially for sale or trade.

Require

Require as useful, just, or proper;

It takes nerve to do what she did

Success usually requires hard work

This job asks a lot of patience and skill

This position demands a lot of personal sacrifice

This dinner calls for a spectacular dessert

This intervention does not postulates a patient's consent

Import

(uncountable) The practice of importing.

Require

Consider obligatory; request and expect;

We require our secretary to be on time

Aren't we asking too much of these children?

I expect my students to arrive in time for their lessons

Import

(uncountable) Significance, importance.

It was a matter of great import.

Require

Make someone do something

Import

A foreigner playing in a sports league.

Require

Have need of;

This piano wants the attention of a competent tuner

Import

(transitive) To bring (something) in from a foreign country, especially for sale or trade.

Require

Executes the code in the module immediately upon loading.

Require('./config').initialize();

Import

(transitive) To load a file into a software application from another version or system.

How can I import files from older versions of this application?

Import

(intransitive) To be important; to be significant; to be of consequence.

Import

(transitive) To be of importance to (someone or something).

Import

(transitive) To be incumbent on (someone to do something).

Import

(transitive) To be important or crucial to (that something happen).

Import

(transitive) To mean, signify.

Import

To express, to imply.

Import

To bring in from abroad; to introduce from without; especially, to bring (wares or merchandise) into a place or country from a foreign country, in the transactions of commerce; - opposed to export. We import teas from China, coffee from Brazil, etc.

Import

To carry or include, as meaning or intention; to imply; to signify.

Every petition . . . doth . . . always import a multitude of speakers together.

Import

To be of importance or consequence to; to have a bearing on; to concern.

I have a motion much imports your good.

If I endure it, what imports it you?

Import

To signify; to purport; to be of moment.

Import

Merchandise imported, or brought into a country from without its boundaries; - generally in the plural, opposed to exports.

I take the imports from, and not the exports to, these conquests, as the measure of these advantages which we derived from them.

Import

That which a word, phrase, or document contains as its signification or intention or interpretation of a word, action, event, and the like.

Import

Importance; weight; consequence.

Most serious design, and the great import.

Import

Commodities (goods or services) bought from a foreign country

Import

An imported person brought from a foreign country;

The lead role was played by an import from Sweden

They are descendants of indentured importees

Import

The message that is intended or expressed or signified;

What is the meaning of this sentence

The significance of a red traffic light

The signification of Chinese characters

The import of his announcement was ambigtuous

Import

A meaning that is not expressly stated but can be inferred;

The significance of his remark became clear only later

The expectation was spread both by word and by implication

Import

Having important effects or influence;

Decisions of great consequence are made by the president himself

Virtue is of more moment that security

Import

Bring in from abroad

Import

Indicate or signify;

I'm afraid this spells trouble!

Import

Facilitates static analysis for bundling tools.

Import * as MathFunctions from './math';

Common Curiosities

Can 'import' be used in Node.js?

Yes, with recent versions, Node.js supports ES6 modules using 'import'.

How do 'require' and 'import' handle module caching?

'Require' caches each module after the first load, while 'import' relies on the module loader's behavior, which may or may not cache modules.

Does 'import' allow conditional module loading?

Yes, 'import()' can be used to conditionally load modules at runtime, allowing for dynamic imports based on conditions.

Is 'require' available in browser JavaScript?

No, 'require' is specific to Node.js and is not available in browsers.

What syntax variations does 'import' offer that 'require' does not?

'Import' provides syntax for default imports, named imports, namespace imports, and dynamic imports, offering greater flexibility than 'require'.

What are the benefits of using 'import' over 'require'?

'Import' allows for asynchronous module loading and more efficient bundling.

What environments primarily use 'require'?

'Require' is primarily used in Node.js environments.

Can I mix 'require' and 'import' in the same project?

While technically possible, it is not recommended due to potential issues with module resolution and execution order.

Can 'require' be used to import JSON files?

Yes, in Node.js, 'require' can be used to directly import JSON files by reading and parsing the JSON into a JavaScript object.

Is 'import' faster than 'require'?

'Import' can be more efficient in terms of execution time when used with static analysis and tree-shaking tools, though 'require' may perform better in scenarios where immediate execution and caching are critical.

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Author Spotlight

Written by

Tayyaba Rehman

Tayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.

Co-written by

Maham Liaqat

Require vs. Import — What's the Difference?

Difference Between Require and Import

Table of Contents

Key Differences

Comparison Chart

Introduced in

Syntax Simplicity

Caching

Dynamic Loading

Execution

Compare with Definitions

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Import

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Common Curiosities

Can 'import' be used in Node.js?

How do 'require' and 'import' handle module caching?

Does 'import' allow conditional module loading?

Is 'require' available in browser JavaScript?

What syntax variations does 'import' offer that 'require' does not?

What are the benefits of using 'import' over 'require'?

What environments primarily use 'require'?