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

user_204840 0
Viewed 3449

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.
typescript
3 Answers

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.

user_11531210

This worked for me:

class MyView1 extends (Polymer.Element as {new(): any}) {
    ...
}
user_50292520
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