How to Fix - Parsing Error: Unexpected Token

Facebook Tweet LinkedIn

If you have encountered an ESLint parsing error with the message Parsing Error: Unexpected Token while working on JavaScript code. Don’t worry you are not alone. This error often occurs when the parser encounters an unexpected token (such as a character or symbol) in the code. In this article, we will walk through the steps to identify and fix the root cause of the parsing error, to get your code back on track.

Causes of Parsing Error: Unexpected Token

This error occurs when the ESLint parser you are using is not compatible with the JavaScript development environment, particularly with the features introduced in JavaScript ES6 and ES7. This parsing error message Unexpected Token shows that there is some kind of code arrangement that is not compatible with the parsing capability of the parser.

Let’s consider an example JavaScript code snippet that may lead to an unexpected token error, specifically when using ES6 syntax in an environment that doesn’t support it.

// Parsing Error: Unexpected Token
const myFunction = () => {
  console.log("Hello, World!");
};

In this example, the use of an arrow function (const myFunction = () => {…}) is an ES6 feature. If your development environment or ESLint configuration is not set up to support ES6, you might encounter an unexpected token error.

How to Fix Parsing Error: Unexpected Token

To resolve unexpected token errors in ESLint parsing due to compatibility issues with the development environment and the evolving JavaScript ES6 and ES7 features, consider the following steps:

Update ESLint and Plugins:

Ensure you have the latest version of ESLint and any relevant plugins installed.

npm install eslint@latest --save-dev

Check ESLint Configuration:

Review and update ESLint configuration to include necessary plugins and support for ES6/ES7.

Update Parser:

If needed, install and use a parser that supports the ECMAScript version you are working with. For example, @babel/eslint-parser or @babel/eslint-parser.

npm install @babel/eslint-parser --save-dev

yarn add -D @babel/eslint-parser.

Now, update the ESLint configuration to use the new parser:

{
  "parser": "@babel/eslint-parser",
  "parserOptions": {
   "ecmaVersion": 6, // Set to JavaScript version
   // Other parser options if needed
  },
  // Other ESLint configurations...
}

Review Code:

Carefully inspect the code for any syntax errors, missing semicolons, mismatched parentheses, or other issues that might trigger unexpected token errors.

Check Dependencies:

Ensure that all required dependencies and libraries are correctly installed and configured.

Use ESLint Extends Configuration:

If you are extending configurations, such as eslint:recommended, ensure that the configuration file is set up correctly.

code{
  "extends": ["eslint:recommended"],
  // Other ESLint configurations...
}

Review Output:

Check the ESLint output in the console for additional details on the parsing error, including the specific file and line number.

Conclusion:

In conclusion, by following the steps given above, you can fix Parsing Error: Unexpected Token in ESLint parsing, ensuring compatibility with the development environment and the evolving JavaScript language features. Hope this guide will help you to resolve the error.

Happy Coding 🙂

Author
Recent Posts

Follow me

Jerry Richard

Cloud Premier Engineer at Cloudera

Jerry grew up in a small town where he enjoyed playing video games. Once out of the nest, he pursued a Bachelor's degree in Computer Engineering. After college, he ultimately landed in the IT industry. Currently, he has over 10 years of experience. In his spare time, Jerry enjoys spending time with his family.

He is creator of this website - unexpectedendoffile.com, A website dedicated to share the mistake and experience learned.