const NO_DOCUMENT_ERROR = 'loadScript cannot be called when document does not exist';

const NO_SRC_ERROR = 'loadScript cannot be called without a src';

type LoadScriptOptions = {

async?: boolean;

defer?: boolean;

crossOrigin?: 'anonymous' | 'use-credentials';

beforeLoad?: (script: HTMLScriptElement) => void;

};

export async function loadScript(src = '', opts: LoadScriptOptions): Promise<HTMLScriptElement> {

const { async, defer, beforeLoad, crossOrigin } = opts || {};

return new Promise((resolve, reject) => {

if (!src) {

reject(NO_SRC_ERROR);

}

if (!document || !document.body) {

reject(NO_DOCUMENT_ERROR);

}

const script = document.createElement('script');

crossOrigin && script.setAttribute('crossorigin', crossOrigin);

script.async = async || false;

script.defer = defer || false;

script.addEventListener('load', () => {

script.remove();

resolve(script);

});

script.addEventListener('error', () => {

script.remove();

reject();

});

script.src = src;

beforeLoad?.(script);

document.body.appendChild(script);

});

}