TypeScript failing to recognize dependency for LitElement

Currently, I am encountering an issue with importing two lit elements in my project, namely RootElement and CustomElement. The problem arises when trying to import CustomElement, which unlike RootElement does not show up properly on the UI. My attempt to include it within the render() method of RootElement also did not yield the desired outcome.

  render() {
    return html`<script
        type="module"
        src="./path/to/customelement.ts"
      ></script>
      <custom-element></custom-element>`;
  }

Upon further inspection, adding an import statement for CustomElement resulted in it being marked as "unused" since it was not utilized anywhere in the codebase:

import { CustomElement } from "./path/to/customelement.ts";

It was only after explicitly including CustomElement in the code (even as a standalone statement) that the element rendered properly without being labeled as "unused". This brings me to question: what adjustments should be made in the tsconfig.js file to ensure this dependency is recognized by the transpiler without the need for extraneous statements?

Answer №1

Referencing the guidelines in the manual about Extra Import Syntax, it is essential to use an import statement without any variables:

Even though the import appears to have no purpose in this instance, executing all the code contained within maths.ts could potentially activate side effects that impact other components.

Side-effects are linked to custom elements being registered, therefore only importing the module is necessary. It should be implemented as shown below:

import "./path/to/customelement.ts";

Similar to what was mentioned in this different SO inquiry, even if a dependency is not utilized, it is still crucial: compilers may eliminate unused variables for convenience, but explicitly stating that there are no variables to utilize ensures that the imported module will be retained and executed before the module that references it.

Answer №2

All I had to do was import the module without setting it as the default export:

import "./path/to/customelement.ts";

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