Type 'SymbolConstructor' has no compatible call signatures

Question

I am following an example in this github repository

My code is

const TYPES = {
    UserService: Symbol("UserService")
};

export default TYPES;

Visual studio code intellisense gives the following error for the above code.

message: 'Cannot invoke an expression whose type lacks a call signature. Type 'SymbolConstructor' has no compatible call signatures.' at: '3,18' source: 'ts'

Symbol definition

interface SymbolConstructor {
    readonly iterator: symbol;
}
declare var Symbol: SymbolConstructor;

This symbol definition is defined in @types/node index.d.ts. When I navigate to the Symbol definition through visual studio code intellisense it took me to the file @types/node index.d.ts.

I just copy paste the code from the repository which I mentioned earlier. So there is no change. I also checked the packages which I installed just to make sure that I installed everything which is there in the repo. Everything looks same.

I am very new to typescript. I looked into some of these links

link 1 and link 2. But I am not able to understand that. Can anyone please clarify on this why this error is coming ?

`SymbolConstructor` is not a class but an interface, so you are getting that error. what is the scenario elaborate I will give an alternate solution — Aravind, Jul 23 '17 at 13:55
I am just following the example from that GitHub link. Just to understand inversely. — shanmugharaj, Jul 23 '17 at 13:57
That variable is been used like this `container.bind(TYPES.UserService).to(UserService);` — shanmugharaj, Jul 23 '17 at 13:58

shanmugharaj · Answer 1 · 2017-07-23T14:51:45.310

I found the mistake I did.

I looked into the repository here. The only change is lies in the tsconfig file

In my tsconfig I had this line

"types": ["reflect-metadata"]

So the compiler is able to look only the @types/node definitions. But when I remove this the compiler is able to find some other definitions from here lib.es2015.symbol.d.ts.

This file is present inside here

/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/node_modules/typescript/lib/lib.es2015.symbol.d.ts

Now that error is gone on the removal of "reflect-metadata" from types in my tsconfig file

score 0 · Answer 2 · answered Dec 06 '18 at 06:01

0

When I had this issue, I found I had neglected to add "lib": ["es6"] to my tsconfig.json file.

There's a good description of this setting in this answer.

answered Dec 06 '18 at 06:01

Jono Job

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Type 'SymbolConstructor' has no compatible call signatures

2 Answers2