isotropic-create

A utility that creates an object with a specific constructor function and prototype object.

Why Use This?

• Safer Object Creation: Avoids issues that can occur when forgetting the new keyword
• Familiar Semantics: Retains the constructor property you'd expect from new
• Explicit Prototypes: Clearly specifies the prototype object for better code readability
• Controlled Inheritance: Provides a cleaner approach to prototypal inheritance

Really though, for most use cases it's better not to directly use isotropic-create. Use isotropic-make instead!

Installation

npm install isotropic-create

Usage

import _create from 'isotropic-create';

// Define a constructor function
const _Person = (name, age) => {
    const instance = _create(_Person, _Person.prototype);

    instance.name = name;
    instance.age = age;

    return instance;
};

// Define methods on the prototype
_Person.prototype.greet = function () {
    return `Hello, my name is ${this.name}`;
};

{
    // Create an instance without using 'new'
    const john = _Person('John', 30);

    console.log(john.greet()); // "Hello, my name is John"
    console.log(john.constructor === _Person); // true
    console.log(Object.getPrototypeOf(john) === _Person.prototype); // true
}

How It Works

isotropic-create uses Object.create() to create a new object with the specified prototype and then adds the constructor property with the right settings. This approach:

1. Avoids the issues that can occur when forgetting the new keyword
2. Explicitly sets the prototype chain
3. Adds the constructor property (non-enumerable) pointing to the constructor function

It's important to note that isotropic-create creates the instance object but does not call the constructor function! A useful pattern is to use it within a constructor function and then return the instance.

API

create(constructorFunction, prototypeObject)

Returns a new object with prototypeObject as its prototype and a constructor property that points to constructorFunction.

Parameters

• constructorFunction (Function): The constructor function to assign to the object
• prototypeObject (Object): The prototype object to use

Returns

• (Object): A new object with the specified prototype and constructor

Contributing

Please refer to CONTRIBUTING.md for contribution guidelines.

Issues

If you encounter any issues, please file them at https://github.com/ibi-group/isotropic-create/issues