Property Accessor

Changelog

This utility provides methods to evaluate and manipulate deeply nested properties of objects using string-based paths like:

"prop1[0].prop2[9]['name']"

You can use it to get or set values dynamically within complex object structures.

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Installation

1npm i property-accessor

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Methods

PropertyAccessor.get(key: string, target: any): any

Retrieves a value from the object using a dot/bracket notation path.

• Parameters:
  • key (string): Property path (e.g. "prop1.prop2[0]['name']")
  • target (object): The target object to evaluate

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PropertyAccessor.set(key: string, value: any, target: any): boolean

Sets a value at the given path. Returns true on success, false otherwise. Automatically creates nested objects and arrays as needed.

• Parameters:
  • key (string): Property path (e.g. "prop1.prop2[0]['name']")
  • value (any): Value to set
  • target (object): The target object to modify

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PropertyAccessor.flat(target: any): any

Returns flat object based on target.

• Parameters:
  • target (object): The target object

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Usage Example

1const { PropertyAccessor } = require('property-accessor');
2
3const target = {
4  users: [
5    { firstName: 'John', surName: 'Doe', age: 25 },
6    { firstName: 'Ann', surName: 'Doe', age: 23 },
7  ],
8};
9
10console.log(PropertyAccessor.get('users[0].firstName', target));
11// Output: John
12
13PropertyAccessor.set('users[1].age', 24, target); // true
14console.log(PropertyAccessor.get('users[1].age', target));
15// Output: 24
16
17PropertyAccessor.set('users[0].children[0]', { name: 'Nick', age: 1 }, target);
18console.log(target.users[0].children);
19// Output: [ { name: 'Nick', age: 1 } ]

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Optional: Instance-Based Usage

For backward compatibility, you can also create an instance and bind a specific target via the constructor:

1const propertyAccessor = new PropertyAccessor({ a: [{ b: 3 }] });
2propertyAccessor.set('a[1].b', 4);
3propertyAccessor.get('a[1].b');
4propertyAccessor.flat();

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