Using dynamic, deferred loading of scripts in JavaScript

Question

Using dynamic, deferred loading of scripts in JavaScript

Is it necessary to create a reference for a dynamic, lazy import that is used multiple times in a script? For example, if there are 2 event handlers importing different functions from the same module:

/* index.js */
window.addEventListener("click", (e) => { 
import(/* webpackChunkName: "myChunk" */ "./my-module.js")
    .then((module) => {
        const result = module.stop();
        console.log('result ', result)
  })    
});

// my-module.js
let value = 0;
export function start(){
    value++
}

export function stop(){
    console.log('stopping');
    return value;
}

This piece of code appears to be working efficiently; the my-module script is only downloaded once, and the state remains available in subsequent calls. Is there an improved method for accomplishing this task? Should a reference be created to the module after its initial import? Are there any specific comments or techniques worth considering?

javascript ecmascript-6 import

Answer 1

Answer №1

Explore Vue SFC

No need to retain the reference as the module is already loaded and exports are identified. However, to avoid repetitive imports each time you call an exported function, consider encapsulating your module into a class:

<script setup>
import {asyncRef} from './utils';
import LazyModule from './lazy-module';
const module = new LazyModule(() => import('./src/my-module.js'));
const value = asyncRef();
</script>

<template>
  <button @click="module.start()">Start</button>
  <button @click="value = module.value">Stop</button>
  <div>value: {{value}}</div>
</template>

my-module.js

export let value = 0;
export function start(){
    value++
}

export function stop(){
    console.log('stopping');
    return value;
}

lazy-module.js

export default class LazyModule{
  constructor(loader){
    return new Proxy(this, {
      get(_, prop){
        const out = async function(){
          const module = await loader();
          return module[prop].apply(module, arguments);
        };
        out.then = async function(cb){
          const module = await loader();
          return Promise.resolve(cb(module[prop]));
        };
        return out;
      }
    });
  }
}

Answer 2

Explore Vue SFC

No need to retain the reference as the module is already loaded and exports are identified. However, to avoid repetitive imports each time you call an exported function, consider encapsulating your module into a class:

<script setup>
import {asyncRef} from './utils';
import LazyModule from './lazy-module';
const module = new LazyModule(() => import('./src/my-module.js'));
const value = asyncRef();
</script>

<template>
  <button @click="module.start()">Start</button>
  <button @click="value = module.value">Stop</button>
  <div>value: {{value}}</div>
</template>

my-module.js

export let value = 0;
export function start(){
    value++
}

export function stop(){
    console.log('stopping');
    return value;
}

lazy-module.js

export default class LazyModule{
  constructor(loader){
    return new Proxy(this, {
      get(_, prop){
        const out = async function(){
          const module = await loader();
          return module[prop].apply(module, arguments);
        };
        out.then = async function(cb){
          const module = await loader();
          return Promise.resolve(cb(module[prop]));
        };
        return out;
      }
    });
  }
}

Using dynamic, deferred loading of scripts in JavaScript

Answer №1

Similar questions

Finding the right property by comparing it with an array of objects in a MongoDB aggregation query

Tips for accessing a value in a multidimensional json array without the key in JavaScript/jQuery?

Trigger a click event on a div element that is nested within a form

Ways to create two distinct "on click" actions for a single image to execute two distinct tasks

Converting JSON data into objects in JavaScript

What is the best approach for manipulating live data in localStorage using ReactJS?

How to efficiently use nested $.each() in DataTables with jQuery

Encountering difficulty in retrieving data from an unidentified JSON array using Javascript

Switching from file:// to http:// in Angular / Ionic is a necessary step when incorporating external scripts like the Disqus directive into your project

Adjust the jQuery resizable handlers on the fly

An error has occurred in Node.js: SyntaxError - Unexpected token ]

What is the best way to seamlessly transition layers from one location to another as the mouse exits and re-enters the window?

Performing optimized searches in Redis

When choosing from multiple dropdown menus, the selected option should be hidden from the other dropdowns

The constricted styles are causing the whole page to bounce (scroll) up and down

Prevent CSS3 columns from reverting back to their original state after being rendered

Once a WordPress user includes a php file

What sets apart Selenium's mouseMove() function from the physical movement of a mouse?

Is there a way to remove <font> tags using Javascript designMode?

The date entered in the input field should also appear in all other textboxes on the