typeerror: prettier.resolveconfig.sync is not a function

2 min read 11-03-2025

The error "TypeError: prettier.resolveConfig.sync is not a function" typically arises when using Prettier, a popular code formatter, within a JavaScript environment. This error signals that the resolveConfig.sync method isn't accessible on the prettier object. This usually means there's a problem with how Prettier is installed or imported into your project. Let's explore the common causes and how to fix them.

Understanding the Error

Prettier's resolveConfig.sync is a synchronous function that finds and loads Prettier configuration files (like .prettierrc or prettier.config.js) within your project. When this function isn't found, it implies Prettier either isn't correctly installed or isn't being imported correctly in your code.

Common Causes and Solutions

Here are the most frequent culprits behind this error and their solutions:

1. Incorrect Prettier Installation

Problem: The most basic reason is a failed or incomplete Prettier installation.
Solution: Verify Prettier is installed correctly. Open your terminal and run:

npm list prettier
# or
yarn list prettier

This command will show you if Prettier is installed and its version. If not, install it using:

npm install --save-dev prettier
# or
yarn add --dev prettier

After installation, restart your development server or IDE to ensure the changes take effect.

2. Outdated Prettier Version

Problem: Older versions of Prettier might not include resolveConfig.sync or might have it deprecated.
Solution: Update Prettier to its latest version. Use these commands:

npm update prettier
# or
yarn upgrade prettier

After updating, restart your environment.

3. Incorrect Import or Usage

Problem: You might be trying to access resolveConfig.sync incorrectly or through a different path within your code. This is particularly common in projects with complex module structures.
Solution: Double-check your import statement. It should look something like this:

const prettier = require('prettier');
//or
import prettier from 'prettier';

const options = prettier.resolveConfig.sync('./your-file.js'); //Path to your file
console.log(options);

Make sure the path you pass to resolveConfig.sync is correct and points to a file (or directory) where Prettier can find configuration. The path should be relative to the location of your JavaScript file.

4. Conflicting Packages

Problem: Other packages in your project might interfere with Prettier's installation or functionality.
Solution: This is more difficult to diagnose. Try creating a minimal, reproducible example. If the error persists in a clean project, it might be a problem with a package dependency. Carefully review your package.json or yarn.lock files to check for any conflicts or unnecessary dependencies.

5. Incorrect Environment Setup

Problem: Sometimes, environment-specific configurations can lead to issues.
Solution: Ensure your project's environment (like Node.js version) is compatible with the current Prettier version. Check Prettier's documentation for compatibility information.

Debugging Tips

If the above solutions don't resolve the issue:

Check your console: Look for any additional error messages or warnings that might provide more context.
Simplify your project: Create a minimal example with only the essential files and dependencies. This can help isolate the problem.
Search for similar issues: Use relevant keywords (e.g., "prettier resolveConfig.sync not a function," "prettier import error") to search online forums or issue trackers.
Review Prettier's Documentation: The official Prettier documentation is an invaluable resource. Refer to it for usage examples and troubleshooting guides.

By systematically working through these solutions and debugging tips, you should be able to resolve the "TypeError: prettier.resolveConfig.sync is not a function" error and get Prettier working correctly in your project. Remember that keeping your dependencies up-to-date is crucial for avoiding many common JavaScript issues.