@randajan/props

Lightweight JavaScript library that simplifies working with Object.defineProperty and Object.defineProperties. It provides intuitive, easy-to-use functions for defining solid, virtual, safe, and cached properties on objects. With this library, you can manage object properties more efficiently, using less code and achieving better readability.

Install

npm install @randajan/props

or

yarn add @randajan/props

Basics

This library provides simplified utilities to define properties on objects with specific behaviors, using four main functions:

1. solid: Creates a straightforward property with a fixed value.
2. virtual: Defines a virtual (getter-only) property.
3. safe: Creates a property with custom getter and setter that reads/writes to a private storage.
4. cached: Defines a property that initializes its value on the first read and caches it.

solid(...) && solids(...)

Defines a property with a fixed, unchangeable value on an object.

Parameters

• obj (Object): The target object to which the property will be added.
• name (String): The name of the property.
• value (Any): The value of the property.
• enumerable (Boolean, default: true): Determines if the property shows up in enumerations.
• configurable (Boolean, default: false): Determines if the property can be redefined or deleted.

Example

solid(myObject, 'constantProp', 42, true, false);

virtual(...) && virtuals(...)

Defines a virtual property, accessible via a getter function, without storing any value on the object.

Parameters

• obj (Object): The target object to which the property will be added.
• name (String): The name of the property.
• get (Function): A function that returns the value when the property is accessed.
• enumerable (Boolean, default: true): Determines if the property shows up in enumerations.
• configurable (Boolean, default: false): Determines if the property can be redefined or deleted.

Example

virtual(myObject, 'dynamicProp', () => Math.random(), true, false);

safe(...) && safes(...)

Defines a property with custom getter and setter functions that interact with a private object, priv, allowing for controlled access to a hidden value.

Parameters

• obj (Object): The target object to which the property will be added.
• priv (Object): A private object storing values.
• name (String): The name of the property.
• set (Function | null): A function to process and set the value on priv (receives new value, current value, and name).
• get (Function | null): A function that retrieves the value from priv (receives current value and name).
• enumerable (Boolean, default: true): Determines if the property shows up in enumerations.
• configurable (Boolean, default: false): Determines if the property can be redefined or deleted.

Example

const priv = { hiddenValue: 100 };
safe(myObject, priv, 'secureProp', 
    (newValue) => newValue * 2, 
    (value) => value + 1, 
    true, false);

cached(...) && cacheds(...)

Creates a property that is initialized lazily, using a reset function upon the first access, and caches this value within a private object.

Parameters

• obj (Object): The target object to which the property will be added.
• priv (Object): A private object storing the cached values.
• name (String): The name of the property.
• reset (Function): A function that provides the initial value upon the first access.
• get (Function | null): A function that retrieves the value (receives the stored value and name).
• enumerable (Boolean, default: true): Determines if the property shows up in enumerations.
• configurable (Boolean, default: false): Determines if the property can be redefined or deleted.

Example

const priv = {};
cached(myObject, priv, 'lazyProp', 
    () => Date.now(),  // Reset only called once on first access
    (value) => `Timestamp: ${value}`, 
    true, false);

Happy hacking

License

MIT © randajan

@randajan/props - Access Points Overview