TypeScript Notes

ts-complex-enum.ts

class Material {
  public static readonly ACRYLIC = new Material(`ACRYLIC`, `AC`, `Acrylic`);
  public static readonly ALUM = new Material(`ALUM`, `AL`, `Aluminum`);
  public static readonly CORK = new Material(`CORK`, `CO`, `Cork`);
  public static readonly FOAM = new Material(`FOAM`, `FO`, `Foam`);

  // private to diallow creating other instances of this type.
  private constructor(public readonly key: string, public readonly id: string, public readonly name: string) {}

  public toString(): string {
    return this.key;
  }
}

declare namespace Material {
  type Keys = Exclude<keyof typeof Material, "prototype">;
}

const materialKeys: Material.Keys[] = [`ACRYLIC`, `FOAM`];
for (const key of materialKeys) {
  const material: Material = Material[key];
  // ...
}

ts-nested-class.ts

class Outer {
  static Inner = class {};
}

declare namespace Outer {
  type Inner = typeof Outer.Inner.prototype;
}

console.log(Outer.name); // Outer
console.log(Outer.Inner.name); // Inner

let _inner: Outer.Inner;

// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

/**
 * Default name is just "Inner".
 * Can get difficult to identify if we log class names, and multiple "Inner" classes exist.
 *
 * Override the static `.name` to return namespaced-name "AnotherOuter.Inner",
 * which mirrors how we reference it in code.
 */

class AnotherOuter {
  static Inner = class {};
}

Object.defineProperty(AnotherOuter.Inner, "name", {
  value: `${AnotherOuter.name}.${AnotherOuter.Inner.name}`,
  writable: false,
});

console.log(AnotherOuter.Inner.name); // AnotherOuter.Inner