TS Conversions

Utilities for safely and unsafely working around TypeScript type checking.

Examples

• trySpecify

  • Successful conversion

    const element: HTMLElement = new Image();
    const elementAsImg = trySpecify(element, HTMLImageElement);
    elementAsImg.src = "image.png";

  • Failed conversion

    const element: HTMLElement = new Image();
    // The next function call will throw, because the object stored in element
    // isn't an instance of `HTMLFormElement`
    const elementAsForm = trySpecify(element, HTMLFormElement);
    elementAsForm.method = "post";

• uncheckedCast

  // element1 has type HTMLElement
  const element1 = uncheckedCast<HTMLElement>(document.getElementById("img"));

  function next(val: number) {
    return val + 1;
  }
  
  const str = "hello";
  const nextStr = next(uncheckedCast(str));

• throwIfNull

  // element1 has type HTMLElement | null
  const element1 = document.getElementById("img");
  
  // element2 has type HTMLElement
  const element2 = throwIfNull(document.getElementById("form"));

Documentation

You can generate the documentation by running the docs script.

Why are the docs full of amoguses?

TSDoc is rough around the edges and VS Code won't format correctly when a @link tag follows some tags such as @return. Amoguses have been inserted to circumvent this problem, and are easy to find and remove when it gets fixed.