loadElement

Load a given source for a given type of element.

Usage

import { loadElement } from '@studiometa/js-toolkit/utils';

const src = '/path/to/my/src.js';
const { event, element } = await loadElement(src, 'script');

if (event.type === 'error') {
  console.log(`Failed to load ${src}: ${event.message}`);
} else {
  console.log(`${src} has been loaded!`);
}

Parameters

• src (string): the source URL to load
• type ('embed' | 'iframe' | 'img' | 'link' | 'script' | 'track'): the type of element that should be used to load the source
• options ({ appendTo?: HTMLElement }): configure the loader behavior
  • options.appendTo (HTMLElement): append the created element to a DOM element

Return value

• Promise<{ event: Event, element: HTMLelement }>: a promise resolving to an object containing both the load event object and the created element

Examples

Avoid loading the same element multiple times

You can combine the loadElement function with the memo function to add an in memory cache layer. This will make the generated function always return the same generated element.

import { loadElement, memo } from '@studiometa/js-toolkit';

const loadElementWithCache = memo(loadElement);
const promise = loadElementWithCache('/path/to/script.js', 'script');
const promise2 = loadElementWithCache('/path/to/script.js', 'script');

console.assert(promise === promise2); // true

const [result, result2] = await Promise.all([promise, promise2]);

console.assert(result === result2);

Cache invalidation

Be aware that the memo function will use a simple arguments.join('') call to generate the cache key, thus ignoring any change in the options parameter of the loadElement function.

const loadElementWithCache = memo(loadElement);

const result = await loadElementWithCache('script.js', 'script', {
  appendTo: document.head,
});
const result2 = await loadElementWithCache('script.js', 'script', {
  appendTo: document.body,
});

console.assert(result === result2); // true

console.log(result.element.parentElement); // document.head
console.log(result2.element.parentElement); // document.head