9 points

Required Parameters for Functions in JavaScript


dashboard

Fri Apr 24 2020 11:32:35 GMT+0000 (UTC)

Posted by @Dimples #javascript #javascript #functions #parameters

 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;
}                               
                                
content_copy Copy

Ooo this is clever! So above, if you don’t provide a name, it’ll use the default instead, which is that function that throws an error.

https://css-tricks.com/snippets/javascript/required-parameters-for-functions-in-javascript/