Confusing "duplicate identifier" Typescript error message

🤔 Confusing "Duplicate Identifier" Typescript Error Message

Are you encountering the dreaded "Duplicate Identifier" error message in TypeScript? Don't worry, you're not alone! This error can be quite confusing, but we're here to help you understand the issue and find easy solutions to fix it. In this blog post, we'll address the common issues that lead to this error, provide step-by-step solutions, and even share code snippets to guide you along the way.

But first, let's take a look at the context around this question:

node_modules/typescript/bin/lib.core.d.ts(83,5): error TS2300: Duplicate identifier 'configurable'.
node_modules/typescript/bin/lib.core.d.ts(84,5): error TS2300: Duplicate identifier 'enumerable'.
node_modules/typescript/bin/lib.core.d.ts(85,5): error TS2300: Duplicate identifier 'value'.
node_modules/typescript/bin/lib.core.d.ts(86,5): error TS2300: Duplicate identifier 'writable'.

You can find all the code and the repo here.

Now that we've understood the problem, let's dive into some solutions:

1. Check Your tsconfig.json

One common cause of the "Duplicate Identifier" error is a misconfigured tsconfig.json. Make sure to check the following properties in your file:

{
    "compilerOptions": {
        "module": "commonjs",
        "noImplicitAny": false,
        "outDir": "built/",
        "sourceMap": true,
        "target": "es5"
    }
}

Double-check that the "target" property is set correctly according to your project's needs. In this case, "es5" is the specified target.

2. Verify Your tsd.json

Another possible culprit is the tsd.json file. Ensure that it is properly configured and references the correct definition files. Here's an example of a correctly configured tsd.json:

{
  "version": "v4",
  "repo": "borisyankov/DefinitelyTyped",
  "ref": "master",
  "path": "typings",
  "bundle": "typings/tsd.d.ts",
  "installed": {
    "node/node-0.10.d.ts": {
      "commit": "6387999eb899d0ba02d37dd8697647718caca230"
    },
    "should/should.d.ts": {
      "commit": "e1182d56ccb192379eade6055d9ba3fb6a0bacc4"
    }
  }
}

Ensure that the tsd.json is pointing to the correct definition files for your project's dependencies.

3. Check for Duplicate Imports

Sometimes, the error is caused by duplicate import statements. Make sure you're not importing the same module multiple times.

import { SomeModule } from 'module'; // Check for duplicate imports

Removing the duplicate import statements should address the "Duplicate Identifier" error.

4. Resolve Version Conflicts

If your project relies on multiple dependencies, it's possible that there may be version conflicts. Make sure all your dependencies are compatible with each other and try updating them to resolve any conflicts.

Alternatively, you can use a package manager like Yarn or npm to handle the version management automatically.

🚀 Call-to-Action

We hope these solutions have helped you resolve the "Duplicate Identifier" TypeScrpit error. Remember to double-check your tsconfig.json, tsd.json, and import statements. If the error persists, feel free to ask for help in the community or raise an issue in the repository.

Has this guide been helpful to you? Let us know in the comments section below or share this post with your fellow developers who might be facing the same issue. Together, we can conquer the "Duplicate Identifier" error and keep coding without any roadblocks! Happy coding! 😄