TS Get Set

100% Type safe get and set functions.

Installation

# npm
npm i ts-get-set

# yarn
yarn add ts-get-set

Usage

import { get, set } from "ts-get-set";

const a = {
  b: 5,
  c: [1, 2, { d: "asdf" }],
};

let d: string = get(a, "c.2.d");
console.log(d); // "asdf"

const updatedA = set(a, "c.2.d", "fdsa");

console.log(updatedA);
// {
//   b: 5,
//   c: [1, 2, { d: "fdsa" }],
// };

d = get(a, "c.2.d");
console.log(d); // "fdsa"
console.log(a.c[2].d); // "fdsa"

Recommended configurations

When using this library it's recommended to turn on these options in your tsconfig.json:

{
  "compilerOptions": {
    /* ... */
    "strict": true,
    "noUncheckIndexAccess": true
  }
}

API

`get`

Gets the value at path of object. If the resolved value is undefined, the defaultValue is returned in its place.

Usage:

const obj = { a: [1, 2, { b: 3 }] };
get(obj, "a.2.b"); // 3

Type:

function get<Obj extends AnyObject, Key extends string, Default = undefined>(
  object: Obj,
  stringPath: Key,
  defaultValue?: Default
): Get<Obj, PathString<Key>, Default>;

`set`

Usage:

const obj = {};
set(obj, "a.2.b", "hello"); // { a: [undefined, undefined, { b: "hello" }] }

Type:

function set<Obj extends AnyObject, Key extends string, Value>(
  object: Obj,
  stringPath: Key,
  value: Value
): Set<Obj, PathString<Key>, Value>;

`stringToPath`

Converts a dot notation string to a path array

Usage:

const path = stringToPath("a.b.2.c.5");

console.log(path); // ["a", "b", "2", "c", "5"]

`PathString`

A type that converts string to a path.

Usage:

type Path = PathString<"a.b.c.1">; // ["a", "b", "c", "1"]

`Get`

A type that gets a property from object at specified path.

Usage:

type NestedProps = Get<{ a: { b: [1, "c"] } }, ["a", "b", "2"]>; // "c";
// or
type NestedProps = Get<{ a: { b: [1, "c"] } }, PathString<"a.b.2">>; // "c";

`Set`

A type that sets the property to a provided value at path.

type Data = { b: number; c: string };
type NewData = Set<Data, ["c", "d"], string[]>; // { c: { d: string[]; } b: number; }
// or
type NewData = Set<Data, PathString<"c.d">, string[]>; // { c: { d: string[]; } b: number; }

Roadmap

Here is the list of features that I want to add in the near future. It's not the strict set of tasks but more of a plan for the development of this package. If you have any suggestions, feel free to open an issue.

get, set and stringToPath 100% type safety (open an issue if you've found some bug).
Support for [] syntax for index access.
Suggestions in dot notation string (may increase compilation time).

License

MIT