define-lazy-prop

What is define-lazy-prop?

The define-lazy-prop npm package allows developers to define properties on an object that are lazily evaluated. This means the value of these properties is only computed when they are accessed for the first time. This can be particularly useful for improving performance by delaying expensive computations or for initializing properties that depend on external resources that might not be immediately available.

What are define-lazy-prop's main functionalities?

Lazy property definition

This feature allows you to define a property on an object that will only compute its value the first time it is accessed. The example demonstrates defining a lazy property 'expensiveValue' on an object, where the value is only computed upon first access.

const defineLazyProp = require('define-lazy-prop');

const obj = {};
defineLazyProp(obj, 'expensiveValue', () => {
  // Imagine an expensive operation here
  return 'value computed';
});

console.log(obj.expensiveValue); // The function is called and value computed now

Other packages similar to define-lazy-prop

lazy-value

Similar to define-lazy-prop, lazy-value allows for the definition of lazy-evaluated values. However, lazy-value is specifically designed for lazy initialization of a single value rather than attaching properties to objects. It's a more focused tool for cases where you only need to lazily initialize a value without attaching it to an object.

README

define-lazy-prop

Define a lazily evaluated property on an object

Useful when the value of a property is expensive to generate, so you want to delay the computation until the property is needed. For example, improving startup performance by deferring nonessential operations.

Install

$ npm install define-lazy-prop

Usage

import defineLazyProperty from 'define-lazy-prop';

const unicorn = {
	// …
};

defineLazyProperty(unicorn, 'rainbow', () => expensiveComputation());

app.on('user-action', () => {
	doSomething(unicorn.rainbow);
});

API

defineLazyProperty(object, propertyName, valueGetter)

object

Type: object

Object to add the property to.

propertyName

Type: string

Name of the property to add.

valueGetter

Type: Function

Called the first time propertyName is accessed. Expected to return a value.

Related

• lazy-value - Create a lazily evaluated value
• import-lazy - Import a module lazily
• p-lazy - Create a lazy promise