uni-app [plugin:uni:mp-inject] Unexpected token

The error message [plugin:uni:mp-inject] Unexpected token in uni-app typically indicates a syntax error or an unexpected character in your code. This can happen for various reasons, such as a missing or incorrect character, or an issue with the way the code is being processed by the build tool.

Here are some steps to troubleshoot and resolve this issue:

1. Check for Syntax Errors

• Look for missing or misplaced characters (e.g., ,, ;, {, }, ], )).
• Ensure that your code is properly formatted, especially in the file where the error is occurring.

2. Inspect the File Mentioned in the Error

• The error message might include a file name or line number where the issue occurred. Inspect that file for any potential issues.

3. Check for Unsupported JavaScript Features

• If you’re using modern JavaScript features (e.g., optional chaining ?., nullish coalescing ??, or arrow functions =>), ensure that they are supported by the build tool or transpiler being used by uni-app.

4. Review the mp-inject Plugin Configuration

• The mp-inject plugin is used for injecting code into mini-program platforms. Check if there are any issues in the configuration or usage of this plugin.
• Ensure that the injected code is valid and properly formatted.

5. Update uni-app and Dependencies

• Ensure that you are using the latest version of uni-app and its dependencies. Run the following commands in your project directory:

  npm install @dcloudio/uni-app@latest
  npm install

6. Clear Cache and Rebuild

• Sometimes, cached files can cause issues. Clear the cache and rebuild your project:

  npm run dev:clean
  npm run dev

7. Check for Third-Party Library Issues

• If you recently added a third-party library, it might be causing the issue. Try removing or updating the library to see if the error persists.

8. Debug with a Minimal Example

• Create a minimal example of your project and gradually add code until you identify the source of the error.

9. Consult the uni-app Documentation

• Refer to the uni-app documentation for guidance on using plugins and resolving common issues.

Example of a Common Issue

If you have code like this:

const obj = { name: 'uni-app' };
console.log(obj?.name);

Ensure that the optional chaining operator (?.) is supported by your build tool. If not, replace it with a traditional check:

console.log(obj && obj.name);