Ooo this is clever! I’m snagging this from David’s blog.
const isRequired = () => { throw new Error('param is required'); };
const hello = (name = isRequired()) => { console.log(`hello ${name}`) };
// These will throw errors
hello();
hello(undefined);
// These will not
hello(null);
hello('David');
The idea here is that it uses default parameters, like how the b parameter here has a default if you don’t send it anything:
function multiply(a, b = 1) {
return a * b;
}So above, if you don’t provide a name, it’ll use the default instead, which is that function that throws an error.