The difference between "require(x)" and "import x"

node.js typescript import require
austinthemassive picture austinthemassive · Oct 11, 2017 · Viewed 156k times · Source

I've just started working on a small node project that will interface with a MongoDB. However, I cannot seem to get the relevant node modules to import correctly, even though I have installed them correctly via npm.

For example, the following code throws an error, telling me that "express has no default export":

import express from "express";

However, this code works:

const express = require("express");

So my question is, what is the difference in how the import and variable/require methods function? I'd like to fix whatever is plaguing my imports on the project, as it seems likely to cause additional problems down the road.

Answer

Always Sunny picture Always Sunny · Oct 11, 2017

This simple diagram that helps me to understand the difference between require and import.

enter image description here

Apart from that,

You can't selectively load only the pieces you need with require but with imports, you can selectively load only the pieces you need. That can save memory.

Loading is synchronous(step by step) for require on the other hand import can be asynchronous(without waiting for previous import) so it can perform a little better than require.

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