What are the benefits of using await-import within a function as opposed to a top level import?

Within a vast code base, you will find await import statements similar to these:

const { "default": MenuView } = await import('./menu/MenuView');
const { "default": MenuViewModel } = await import('./menu/MenuViewModel');

Presented here is a broader context:

import { View } from 'backbone.marionette';
import RivetsBehavior from 'behaviors/RivetsBehavior';
import tpl from './Mask.HeaderView.html';
import './Mask.HeaderView.scss';


export default View.extend({
  behaviors: [RivetsBehavior],
  template: tpl,

  regions: {
    menu: ".mask-menu"
  },

  async onRender() {
    const { "default": MenuView } = await import('./menu/MenuView'); // <---------------
    const { "default": MenuViewModel } = await import('./menu/MenuViewModel'); // <-----

    const oMenuViewModel = new MenuViewModel();
    oMenuViewModel.setOptions(this.options);

    this.showChildView('menu', new MenuView({
        model: oMenuViewModel
    }));
  }
});

I have relocated the imports to the top of the file:

import { View } from 'backbone.marionette';
import RivetsBehavior from 'behaviors/RivetsBehavior';
import tpl from './mask.HeaderView.html';
import './mask.HeaderView.scss';
import MenuView from './menu/MenuView'; // <---------------------------- here
import MenuViewModel from './menu/MenuViewModel'; // <------------------- here


export default View.extend({
  behaviors: [RivetsBehavior],
  template: tpl,

  regions: {
    menu: ".maskn-menu"
  },

  async onRender() {
    // const { "default": MenuView } = await import('./menu/MenuView'); <------------ no
    // const { "default": MenuViewModel } = await import('./menu/MenuViewModel'); <-- no

    const oMenuViewModel = new MenuViewModel();
    oMenuViewModel.setOptions(this.options);

    this.showChildView('menu', new MenuView({
        model: oMenuViewModel
    }));
  }
});

Everything appears functional. However, I am concerned that there may be something overlooked.

Interrogations

  1. What prevents simply situating those await imports alongside other imports at the beginning of the file?
  2. Could this potentially impact performance? In the provided example, only 2 await-imports exist, but consider a scenario with a file containing 60 functions, each with 2 await-imports importing different entities.
  3. Is this relevant to user interface experience considerations (e.g., preventing UI blockage)?

Answer №1

Using static imports should function correctly as intended. Both methods are effective.

However, when dynamically importing modules, there may be some advantages in certain scenarios:

When modules are imported statically, they are executed before the importing module runs. On the other hand, dynamic imports within the onRender function result in the modules being evaluated only when the function is called for the first time.

This approach allows for delaying the execution of imported modules until they are actually necessary. If onRender is never invoked, these modules will not be imported at all.

Therefore, while your version will still work, the original method may offer some improvements (depending on how the onRender function is triggered).

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

In what scenarios is it most beneficial to utilize an isolate scope in Angular?

The AngularJS guide states that the isolate scope of a directive isolates everything except models explicitly added to the scope: {} hash object. This is useful for building reusable components because it prevents unintended changes to your model state, al ...

Ways to clear dropdown selection in Vue based on a specific condition?

I am currently developing a dropdown menu for selecting visit status options, which include "pending," "canceled," "rejected," and "approved." In the case of an approved visit status, I would like the dropdown selection to only display the options for "can ...

Drop items next to the specified keys. Vanilla JavaScript

I am trying to create a new array of objects without the gender field. Can you identify any mistakes in my code? let dataSets = [ { name: "Tim", gender: "male", age: 20 }, { name: "Sue", gender: "female", age: 25 }, { name: "Sam", gender: "m ...

Steps for setting up single sign on in an Angular 2 application

Currently, I am working on a web application that has been developed using angular2. One of the requirements for this application is to incorporate a single sign-on feature, where users do not have to manually input their login credentials. Instead, the ap ...

How can I determine in JavaScript if the Backspace key is being long pressed on iOS or Android devices?

In the process of developing a web application using Vue.js, I encountered an issue with detecting long presses of the Backspace key on desktop keyboards (Windows PCs specifically). On desktop, the event triggers multiple times as long as the Backspace key ...

Steps to obtain the precise source code of a webpage

Is there a way to download the exact source code of a webpage? I have tried using the URL method and Jsoup method, but I am not getting the precise data as seen in the actual source code. For example: <input type="image" name="ctl00$dtlAlbums$ct ...

Updating TextBox Content upon task accomplishment

I'm currently working on a WinForms application with two forms. In the first form, users input information and then click a button to move to the second form. Upon doing so, form1 is hidden, form2 loads, and a task (whose function is defined in form1) ...

Comma styling in JavaScript

What is the reasoning behind developers choosing to format commas in code this particular way? var npm = module.exports = new EventEmitter , config = require("./lib/config") , set = require("./lib/utils/set"); As opposed to this formatting style? va ...

Assign a specific attribute to a checkbox, gather all selected attributes, and transmit them using jQuery

I have a system generated table with approximately 800 rows that needs checkboxes added for users to select specific rows for more information. I can add a checkbox column to the entire table at once, but I don't want to manually assign values to each ...

What is the best way to invoke a function in Typescript while retrieving data?

Is it possible to run a query in my main.ts file with another ts file and then pull the result of the query into another file? If so, how can this be achieved? Here is an example from my main.ts file: async function getAllTips() { const tips: any = []; ...

Error: The function referenced is not defined when the page loads

Trying to incorporate two different script tags in a single HTML page has been quite a task for me. The first script tag contains the location of a JS file that I need to use for a specific function, while the second script tag is where I have written anot ...

Activate the opening of a .docx file in a new tab by utilizing an anchor tag

I have attached a docx file containing the terms and conditions for our project. Now, I would like to open it in a new tab. By clicking this link, you can view the <a title="click to view terms and conditions" style="color:blue;" target="_blank" href ...

Guide on integrating snackbar into a function within Angular 7

I currently have a mat-table with 6 columns. The 5th column displays the status of the job, which can be Completed, Running, or Pending. I've added two buttons - Stop and Re-Run. When a user clicks on the Stop button, I want the job to stop executing ...

Incorrect configuration file for karma

To simplify the configuration of the karma config file, I have utilized variables to store specific parts of the path. var publicfolder = "public" var mypath = "packages/vendor/package/"; files: [ publicfolder+'/assets/libs/jquery/dist/jquery.js&a ...

if the current value in the field surpasses the specified value in JavaScript

Looking to incorporate an additional condition into a JavaScript function initial condition if (content.length==elmnt.maxLength) new condition if (content.length==elmnt.maxLength && current form field value > 1400) How can I properly implement the ...

In Typescript, if at least one element in an array is not empty, the function should return false without utilizing iterators

My current approach involves receiving a string array and returning false if any of the elements in the array is false. myMethod(attrs: Array<String>) { for (const element of attrs) { if (!element) { return false; } } ...

How can I include JavaScript files in Maya or 3DS Max?

My dilemma lies in attempting to access a js file on Maya (2013) and 3ds max (2016) without any available three.js importers for these particular softwares. How can I effectively import a js file on either Maya or 3ds max? Alternatively, are there other ...

What is the best way to use jQuery to insert this block of HTML into a page from a JSON response?

<script type="text/javascript"> var dataString2 = 'run=captchagood&comment=' + comment; $.ajax({ type: "POST", url: "process.php", data: dataString2, dataType: "json", error: 'error', success: function ...

Merge Various Ng-Loops

I am working with an HTML structure in which each child has varying lengths: <div ng-repeat='element in treeView'> <div ng-repeat='element1 in element.children'> <div ng-repeat='element2 in element1.chil ...

Error encountered: Unable to assign a value to the property 'className' as it is undefined in JavaScript

Having trouble adding a classname to my JavaScript code which looks like so: var a = document.querySelectorAll('.nav-tabs'); for(var i=0 ; i<a.length; i++){ a[i].addEventListener('click',function(){ a[i].classList.ad ...