NPM zone.js Package

Table of Contents

• Overview
• Usage
  • Quick Start
  • Configure zone.js
  • Zone Injection
• Implementation Guide
  • Core Concepts
    • Zones
    • Tasks
    • Tasks vs Promises
  • API Reference
    • zone.js API
    • zone-patch API
  • Best Practices

Overview

zone.js is a library that allows developers to create custom zones for running code in a protected environment. This can be useful for isolating code that could potentially cause errors, or for running code in a different context (e.g. a different thread).

Usage

Quick Start

To get started with zone.js, you can install it using NPM:

npm install zone.js --save

Then, you can import zone.js into your application:

import 'zone.js';

Configure zone.js

zone.js can be configured using the Zone.config object. This object allows you to specify a number of options, such as the default zone name, the error handling behavior, and the list of patches to apply.

For example, to change the default zone name to "MyZone", you can use the following code:

Zone.config({
  name: 'MyZone'
});

Zone Injection

Zone injection is a mechanism that allows you to inject zones into functions and objects. This can be useful for isolating code that could potentially cause errors, or for running code in a different context.

To inject a zone into a function, you can use the Zone.bind method:

const myFunction = Zone.bind(function() {
  // Code to be executed in the zone
});

To inject a zone into an object, you can use the Zone.fork method:

const myObject = Zone.fork(function() {
  // Object to be executed in the zone
});

Implementation Guide

Core Concepts

Zones

A zone is a protected environment in which code can be executed. Zones can be used to isolate code that could potentially cause errors, or for running code in a different context.

Tasks

A task is a unit of work that is executed in a zone. Tasks can be created using the Zone.run method:

Zone.run(() => {
  // Code to be executed in the zone
});

Tasks vs Promises

Tasks and promises are both used for asynchronous programming. However, there are some key differences between the two:

• Tasks are executed in a specific zone, while promises are not.
• Tasks can be canceled, while promises cannot.
• Tasks can be used to create complex execution patterns, while promises are more straightforward.

API Reference

zone.js API

The zone.js API provides a number of methods for creating and managing zones.

• Zone.create(properties): Creates a new zone.
• Zone.bind(function, properties): Injects a zone into a function.
• Zone.fork(properties): Injects a zone into an object.
• Zone.run(function, args): Executes a function in a zone.
• Zone.get(object): Gets the zone that is associated with an object.

zone-patch API

The zone-patch API provides a number of patches that can be applied to JavaScript APIs. These patches allow you to run code in zones, even when the APIs are not designed to support it.

• patch(target, name, patch): Patches the specified target with the specified patch.
• unpatch(target, name): Unpatches the specified target.

Best Practices

When using zone.js, it is important to follow a few best practices:

• Only patch APIs that you need to patch. Patching too many APIs can lead to performance problems.
• Avoid using zone.js in performance-critical code. Zone.js can add overhead