object-bystring

Access and alter deeply nested object properties by string notation

Purpose

Let's say you want to change a something nested in this object:

var objA = {
  name: "tamb",
  address: {
    street: "123 fake street",
    town: "fake town",
    zip: "00000",
    state: "Fake State",
    city: "Fake City",
    POBoxes: [1234, 23213, 2321],
  },
  dependents: [
    {
      name: "John Doe",
      age: 55,
    },
    {
      name: "Jane Doe",
      age: 44,
    },
  ],
};

You coould easily write objA.dependents[1].age = 45;
Or even var indx = 1; objA.dependents[indx].age = 45;

No issue here.

But let's say you are trying to pass along an object (objB) of commands. Those commands should dictate what to change in objA.

How do you easily do this?

{
 'address.street': '345 Faker Way',
 'dependents[1].age': 45,
 'address.POBoxes[2]': 43278
}

With byString you can generate paths to object values and either set or get those values.

Latest Docs:

https://github.com/tamb/object-bystring

Demo

https://codesandbox.io/embed/object-bystring-demo-i3845d?fontsize=14&hidenavigation=1&theme=dark

installation

npm install --save object-bystring

Usage

You can import either a utility method, or a polyfill to add this functionality to the Object prototype.

// util method
const { bystring } = require("object-bystring");
import { byString } from "object-bystring";

Using the example above:

Setting Values

byString(object, key, value)

byString(objectA, "path.to.field", "new value");

setting values for fields that don't exist will add them to the object. Setting values for array indexes that don't exist will add them to the array and other indexes will be undefined.

### Getting Values

#### `byString(object, key);`

```js
const finger = byString(person, "arm[0].hand.fingers[3]");

const randomFinger = byString(person`arm[0].hand.fingers[${number}]`);

Getting values for fields that don't exist will return undefined.

Performance

v7 Performance Improvements

v7 has a 21.12% performance improvement for 1,000,000 iterations over v6.

Performance test results:

• Setting values: 15.78% faster
• Getting values: 26.95% faster
• Overall: 21.12% faster

The optimization includes:

• Improved parsing algorithm (replaced regex with character-by-character parser)
• Modular architecture with separated concerns
• Enhanced error handling and edge case coverage
• Better TypeScript support and type safety

All existing functionality is preserved with full backward compatibility.

Attribution

Thank you, Ray for the original Stackoverflow answer, which is the inspiration for this project. https://stackoverflow.com/questions/6491463/accessing-nested-javascript-objects-with-string-key

Check out his github and so profile below:

https://github.com/raybellis

https://stackoverflow.com/users/6782/alnitak