'new' expression, whose target lacks a construct signature in TypeScript

Question

We have the following TestComponent.ts TypeScript class:

01: import TestVectorLayer from \'./TestVectorLayer\'
02: 
03: export class TestCompone         


        

Answer 1

Here's a simplification of the question:

const TestVectorLayer = function(layerName: string) {
};

const layer = new TestVectorLayer("");

The error is happening because TestVectorLayer doesn't have a new signature, so layer is implicitly typed as any. That errors with --noImplicitAny.

You can fix this by switching to a class, but in your case this seems a bit more complicated because the inheritance is done by the underlying framework. Because of that, you will have to do something a bit more complicated and it's not ideal:

interface TestVectorLayer {
  // members of your "class" go here
}

const TestVectorLayer = function (this: TestVectorLayer, layerName: string) {
  // ...
  console.log(layerName);
  ol.layer.Image.call(this, opts);
} as any as { new (layerName: string): TestVectorLayer; };

ol.inherits(TestVectorLayer, ol.layer.Image);

export default TestVectorLayer; 

Then in the file with TestComponent:

const layer = new TestVectorLayer(layerName); // no more compile error