const html = `
<html>
<h1>this is a title</h1>
</html>
`;
const doc = new JSDOM(html).window.document;
const title = NullSafety.start(doc)
.next(o => o.querySelector('h1'))
.next(o => o.textContent)
.resultAlty('title-for-failed');
console.log(title);
// output: this is a titleconst title = NullSafety.start(doc)
.next(o => o.querySelector('h1'))
// return: HTMLHeadingElement | null
.next(o => o.textContent)
// argument: HTMLHeadingElement (not nullable *>_<)b!
// return: string | null
.resultAlty('title-for-failed');
// return: string (not nullable *>_<)b!Use TypeScript & TypeScript compiler option: strictNullChecks(or strict)
{
"compilerOptions": {
"strictNullChecks": true,
}
}
// or
{
"compilerOptions": {
"strict": true,
}
}