Answer by jerryurenaa for How to check if multiple array keys exists

I usually use a function to validate my post and it is an answer for this question too so let me post it.

to call my function I will use the 2 array like this

validatePost(['username', 'password', 'any other field'], $_POST))

then my function will look like this

 function validatePost($requiredFields, $post)    {        $validation = [];        foreach($requiredFields as $required => $key)        {            if(!array_key_exists($key, $post))            {                $validation['required'][] = $key;            }        }        return $validation;    }

this will output this

"required": ["username","password","any other field"    ]

so what this function does is validate and return all the missing fields of the post request.