Promisification
Promisification
Promisification it’s the conversion of a function that accepts a callback into a function returning a promise.
Write a function promisify(f) that receives a function fthat accepts a callback f( ...args, callback) and
returns a function that returns the equivalent Promise object
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Promisify</title>
</head>
<body>
<script>
function promisify(f) {
// Fill the code
};
function loadScript(src, callback) {
let script = document.createElement('script');
script.src = src;
script.onload = () => callback(null, script);
script.onerror = () => callback(new Error(`Script load error for ${src}`));
document.head.append(script);
}
let loadScriptPromise = promisify(loadScript);
loadScriptPromise("https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js").then(
(r) => alert("script loaded")
).catch(alert);
</script>
</body>
</html>
See https://javascript.info/promisify