Safely create dot notation

Dot notation is widely used in popular library such as lodash, mongodb,immutable.js (not really dot notation but same same) etc. This library utilize Typescript's conditional type to help create a dotted path notation in a type-safed way. Requires Typescript >= 2.9

import { DottedPath } from 'dotted-path';

type TestType = {
    obj: { num: number };
    str: string;
    bool?: boolean;
    keyA: TestType;
    keyB?: TestType;
    keyC: TestType | null;
    keyD: TestType | undefined;
    keyE: TestType[];
    keyF?: TestType[];
    keyG: TestType[] | null;
    keyH: TestType[] | undefined;
};

const pathNav = DottedPath<TestType>();

pathNav.goTo('obj').goTo('num').end() // obj.num
pathNav.goTo('keyA').goTo('str').end() // keyA.str
pathNav.goTo('keyA').goTo('keyB').goTo('keyC').goTo('keyD').goTo('keyE').goTo(0).goTo('keyF').goTo(1).end() // keyA.keyB.keyC.keyD.keyE.0.keyF.1

// skip index will ignore index segments on array type, which is useful for some library like mongodb's query criteria
DottedPath<TestType>({ skipIndex: true }).goTo('keyE').goTo(0).goTo('obj') // keyE.obj

// alternatively, you can also skip a segment manually
pathNav.goTo('keyE').goTo(0, { ignore: true }).goTo('obj') // keyE.obj

// or you can append a segment that are not related to provided type
pathNav.goTo('keyE').append('$').goTo('obj') // keyE.$.obj