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Extract Updated And New Fields

Identifies both changed and newly added fields between two objects, including deep/nested changes.

Import​

import { extractUpdatedAndNewFields } from 'nhb-toolbox';

Usage​

Basic Usage​

const original = { name: 'John', age: 30 };
const updated = { name: 'Jane', age: 30, role: 'admin' };
const changes = extractUpdatedAndNewFields(original, updated);
// Returns { name: 'Jane', role: 'admin' }

API Reference​

Type Parameters​

NameDescription
TType of base object
UType of potential new fields

Parameters​

NameTypeDescription
baseObjectTOriginal reference object
updatedObjectFlattenPartial<T> & FlattenPartial<U>Modified object

Returns​

Combined object with both changed and new fields (FlattenPartial<T> & FlattenPartial<U>)

Key Features​

  1. Changed Fields: Detects modified values (deep comparison)
  2. New Fields: Identifies newly added keys
  3. Nested Objects: Recursively compares object structures
  4. Type Safety: Maintains proper TypeScript typing

Examples​

With Nested Objects​

const v1 = { user: { id: 1 }, settings: {} };
const v2 = { user: { id: 1, name: 'Alice' }, settings: { darkMode: true } };
extractUpdatedAndNewFields(v1, v2);
// Returns { user: { name: 'Alice' }, settings: { darkMode: true } }

Mixed Changes​

const config = { timeout: 30 };
const updatedConfig = { timeout: 60, retries: 3 };
extractUpdatedAndNewFields(config, updatedConfig);
// Returns { timeout: 60, retries: 3 }

Limitations​

  1. Circular References: Not supported
  2. Array Changes: Treats arrays as atomic values
  3. Special Types: May not handle custom class instances properly

Type Definitions​

type GenericObject = Record<string, any>;
type FlattenPartial<T> = Partial<{ [K in keyof T]: T[K] }>;
  • API response diffing
  • Form change detection
  • State management updates
  • Configuration version comparison