deepGet.md

title	tags	author_title	author_url	author_image_url	description	image
deepGet	object intermediate	Deepak Vishwakarma	https://github.com/deepakshrma	https://avatars2.githubusercontent.com/u/7682731?s=400	Implementation of "deepGet" in typescript, javascript and deno.	https://www.positronx.io/wp-content/uploads/2018/11/positronx-banner-1152-1.jpg

Returns the target value in a nested JSON object, based on the keys array.

Compare the keys you want in the nested JSON object as an Array. Use Array.prototype.reduce() to get value from nested JSON object one by one. If the key exists in object, return target value, otherwise, return null.

// Guard
function isString<T = any>(str: string | T): str is string {
  return typeof str === "string";
}

const deepGet = (
  obj: any,
  keys: string | (string | number)[],
  delimiter = "."
) => {
  if (isString(keys)) {
    keys = keys.split(delimiter);
  }
  return keys.reduce((xs, x) => (xs && xs[x] ? xs[x] : null), obj);
};

let index = 2;
const data = {
  foo: {
    foz: [1, 2, 3],
    bar: {
      baz: ["a", "b", "c"],
    },
  },
};
deepGet(data, ["foo", "foz", index]); // 3
deepGet(data, ["foo", "bar", "baz", 8, "foz"]); //undefined
deepGet(data, "foo.foz.2"); // 3
deepGet(data, "foo->foz->2", null, "->"); //3
deepGet(data, "foo.bar.baz.8.foz", null); //null