[ts] Duplicate function implementation

[dpindusa]

Steps to Reproduce:

1. Create 1.ts file (Code as mentioned below)
2. Create 2.ts file (Code as mentioned below)
3. Create tsconfig.json using tsc -init. (This step is not mandatory)
4. Observer red underline under the function name

VS Code Version: 1.24.0
TypeScript Version: 2.3.4
OS Version: Windows 8.1 Enterprise

Search Terms: TypeScript Visual Studio Code [ts] Duplicate function implementation

Code

//1.ts File
function test(){
    console.log("File 1 Error");
}

//2.ts File
function test(){
    console.log("File 2 Error");
}

Expected behavior:

Actual behavior:

Related Issues: #10804

[RyanCavanaugh]

These functions are in the global scope and only one of them can exist at a time.

[brikou]

In order to prevent functions to be in global scope, you can add export {}; on top (or just export this function):

// 1.ts
export {};

function test(){
    console.log("File 1 Error");
}

// 2.ts
export {};

function test(){
    console.log("File 2 Error");
}

see https://stackoverflow.com/questions/40900791/cannot-redeclare-block-scoped-variable-in-unrelated-files

[xgqfrms]

@brikou Thanks a lot!

1. global scope
2. export {}; ES module, local module scope

[kyoonart]

good

[MuhammadAbdullah54321]

This gives error in the console that
"Uncaught ReferenceError: exports is not defined"

[davschne]

Well, the suggested solution works if I'm using ES modules, but what about when I'm dealing with CommonJS modules? The same error occurs, but there doesn't appear to be a way to fix it. If I add export {}; I get SyntaxError: Unexpected token 'export' when trying to run the generated JS in Node. My sense is that when using "module": "commonjs" in tsconfig.json, such checks should be disabled. @RyanCavanaugh, thoughts?

[andrewbranch]

export {} is downleveled in "module": "commonjs": https://www.typescriptlang.org/play?module=1#code/KYDwDg9gTgLgBAbwL4G4BQQ

If you’re writing .js files that you’re not going to compile, you can get the same effect of modulification with module.exports = {}.

[davschne]

I guess I did something wrong before, because it's working now. Thanks, @andrewbranch!