nested-object-map

NestedObjectMap Class

Deep convert a nested Object into a ES6 Map

npm install nested-object-map

Usage

new NestedObjectMap([object])

The NestedObjectMap Class extends Map and behaves the same way with the difference that the passed objects field values will be mapped. If the object is nested (containing more instances of Object) references to those objects will be mapped as well. Sub-objects will be iterated and their fields will be mapped just the same but their field names will be prefixed with its path. Cyclic references and other objects (eg. arrays) will be mapped as reference. Scalar values are mapped as scalar values, setting them on the map will not change the original objects value.

const NestedObjectMap = require('nested-object-map');

const config = new NestedObjectMap({
  api: {
    http: {
      auth: {
        token: 'secret'
      }
    }
  }
});

const authToken = config.get('api.http.auth.token');
const { token } = config.get('api.http.auth');

console.dir(authToken); // "secret"
console.dir(token); // "secret"

NestedObjectMap.mapObject([object])

You can map another objects fields to the Map (similar to a "deep merge"). This is the same method the constructor calls.

config.mapObject({
  api: {
    http: {
      port: 8080
    }
  }
});

console.dir(config.get('api.http.port')); // 3000
console.dir(config.get('api.http.auth.token')); // "secret"

Use case

It can help you to access values contained deep within nested objects more easily and without the need of too many safe guards. It's probably most useful when dealing with nested objects with unreliable structure.

if (object && object.api && object.api.http && object.api.http.auth) {
  const token = object.api.http.auth.token;
}

// VS

const config = new NestedObjectMap(object);
const token = config.get('api.http.auth.token');

Related

There are similar modules for flat objects:

• ES6-Mapify
• object2map
• object-to-map