Function toGetter

Wraps the given value of type T in a Getter<T>. A Getter<T> can be used like a one-time ad-hoc version of an OptionalLens. In most cases however, using an OptionalLens is the better choice.

Given the following type and values:

type Test =
  | number
  | {
      x: Array<number>;
      a: {
        b: number;
      };
  | {
      a: {
        b: string;
      }
    }
};

let t1: Test = 42;
let t2: Test = { x: [1, 2, 3] };
let t3: Test = { a: { b: 'Test' } };

you could get the following results with toGetter:

const b1 = toGetter(t1).k('a').k('b').get(); // => undefined (inferred as number | string | undefined)
const b2 = toGetter(t2).k('a').k('b').get(); // => undefined (inferred as number | string | undefined)
const b3 = toGetter(t3).k('a').k('b').get(); // => 'Test' (inferred as number | string | undefined)
const x1 = toGetter(t1).k('x').k(1).get(); // => undefined (inferred as number | undefined)
const x2 = toGetter(t2).k('x').k(1).get(); // => 2 (inferred as number | undefined)
const x3 = toGetter(t3).k('x').k(1).get(); // => undefined (inferred as number | undefined)