CODEWITHSUNDEEP
typescript
cthulhu
cthulhu

Reputation: 3169

"Call target does not contain any signature" for call to super() without typings file

I'm trying to make Polymer 2.0 work with Typescript and am running into issues when making a constructor where libraries - including Polymer 2 - do not expose a proper typings file. In the simplest case:

class MyView1 extends Polymer.Element {
    public static is = 'my-view1';

    constructor() {
        super(); // [ts] Call target does not contain any signature
    }
}

To make it compile at all without the constructor, I've done a declare var Polymer: any; in a main .d.ts file.

Now, I have two questions:

  1. How (if at all) can I make typescript ignore this and just assume there's a super constructor it can call?
  2. How (if at all) do I declare a typings file that contains a signature for the super class? I haven't been able to find the right documentation for this (and the various use cases I've run into so far) yet.

Upvotes: 7

Views: 3521

Answers (3)

Ouédraogo Wendé Gûudi Alban
Ouédraogo Wendé Gûudi Alban

Reputation: 21

This worked for me:

class MyView1 extends (Polymer.Element as {new(): any}) {
    ...
}

Upvotes: 0

Cody
Cody

Reputation: 10015

Why

Usually, this is because you there is conditional logic which alters what the superclass can be. For instance -- 

class A {
    constructor() {
        super(/* anything */);
    }
}
class B {
    constructor() {
        super(/* anything */);
    }
}

var X = { prod: A, qa: A, dev: B, mock: B }[ environment.type ];  // inline map

class C extends X {
    constructor() {
        super(/* anything */);
    }
}

-- can yield this behavior if type is not even declared on environment, or [potentially] if TypeScript especially thinks that X could be something other that a class which takes the arguments being provided by the subclass.

Upvotes: 0

Saravana
Saravana

Reputation: 40554

You can just expand your declaration to include a constructor in the Element property:

declare var Polymer: {
    Element: {
        new ();
    }
};

For your second question, you can just move this to a *.d.ts file. See the documentation on creating declaration files.

Upvotes: 2

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