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If you’ve ever had the following error message displayed on your compute when using Javascript: “uncaught referenceerror: require is not defined“. But if you’re still in the dark and have no idea what this actually means, don’t worry! This article will teach you how to fix the problem so that your computer won’t crash when you hit that error again in the future.
Why does “uncaught referenceerror: require is not defined” happen?
This is a common mistake while using Javascript. Sometimes when you run the program, you will get the following message error in your browser:
Uncaught ReferenceError: require is not defined
The error occur because your JavaScript environment doesn’t know how to handle the require() functions. Require() is an function that node.js integrates into the environment. Therefore, when you launch node on the terminal, you’re running an environment that has the require(). But require() is not a browser-specific. So, when you try to make the browser execute your code, it hasn’t require().
How to fix the error “Uncaught referenceerror: require is not defined”
For handling errors, now you’ll need to make some decisions about how you manage the server-side JavaScript scripts.
There are three choices:
- Use <script>tags
- CommonJS Deployment . Synchronous dependencies like Node.js
- AMD Deployment.
Option 1: CommonJS Deployment Method
CommonJS client-side implementations includes:
(most of them ) require the building step prior to install
- Browserify – You are able to use the majority of Node.js modules inside the browser.
- Webpack is a complete solution to do everything (bundle CSS, JS etc.). Popularized by the rise of React.js. This can be quite problematic.
- Rollup-New Candidate. Make use of ES6 modules. This includes tree-shaking capabilities (removing any code that is not being used).
Option 2: AMD Deployment Method
With this way, the problem will be solved by adding require() through using Request JS.
After downloading and installing the latest RequireJS version. Then, you’ll need to invoke the script in the main HTML header in the following manner:
<!DOCTYPE html>
<html>
<head>
<title>RequireJS Tutorial</title>
<script data-main="scripts/app" src="scripts/require.js"></script>
</head>
<body>
<h1 id="headertitle">Sample about RequireJS Tutorial</h1>
</body>
</html>
requirejs(["lodash"], function (lodash) {
const headerEl = document.getElementById("headertitle");
headerEl.textContent = lodash.upperCase("Fix Uncaught ReferenceError");
});
While waiting for the DOM to download, you can add the following code:
document.addEventListener("DOMContentLoaded", function () {
requirejs(["lodash"], function (lodash) {
const headerEl = document.getElementById("headertitle");
headerEl.textContent = lodash.upperCase("Fix Uncaught ReferenceError");
});
});
<!DOCTYPE html>
<html>
<head>
<title>RequireJS Tutorial</title>
<script src="scripts/require.js"></script>
</head>
<body>
<h1 id="headertitle">Sample about RequireJS Tutorial</h1>
<script>
document.addEventListener("DOMContentLoaded", function () {
requirejs(["scripts/lodash"], function (lodash) {
const headerEl = document.getElementById("headertitle");
headerEl.textContent = lodash.upperCase("Fix Uncaught ReferenceError");
});
});
</script>
</body>
</html>
Option 3: Use the ES6 module syntax
You also can fix the error just by using the ES6 module syntax rather than require. For example:
// math.js
function add(a, b) {
return a + b;
}
// named export
module.exports = {
add,
};
// subtract.js
function subtract(a, b) {
return a - b;
}
// default export
module.exports = subtract;
// main.js
const { add } = require("./math"); // named import
const subtract = require("./subtract"); // default import
console.log(add(1, 2));
console.log(subtract(1, 2));Below is the same instance using the syntax of an ES6 import and export module:
// math.js
function add(a, b) {
return a + b;
}
// named export
module.exports = {
add,
};
// subtract.js
function subtract(a, b) {
return a - b;
}
// default export
module.exports = subtract;
// main.js
const { add } = require("./math"); // named import
const subtract = require("./subtract"); // default import
console.log(add(1, 2));
console.log(subtract(1, 2));Here is the similar instance using the module syntax of ES6 import and export:
// math.js
// named export
export function add(a, b) {
return a + b;
}
// subtract.js
function subtract(a, b) {
return a - b;
}
// default export
export default subtract;
// main.js
import { add } from "./math"; // named import
import subtract from "./subtract"; // default import
console.log(add(1, 2));
console.log(subtract(1, 2));It should be emphasized that you can give the default import whatever name you choose in both examples. In this instance, that suggests that the subtract function import might be used similarly:
// main.js
import foo from "./subtract";
console.log(foo(1, 2));Additionally, you may use export default on anonymous functions in the aforementioned subtract.js module:
// subtract.js
export default function (a, b) {
return a - b;
}Conclusion
Through the above article, we have given some instructions to handle Javascript errors “uncaught referenceerror: require is not defined”. Read and choose the method that works for you. If you have any difficulties, you can contact us immediately or leave a comment below. Thanks for reading!
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