Javascript to PHP conversion

Question

I've got one javascript port of the libphonenumber package and it has the function below:

function cleanPhone(a){
 a=a.replace(/[^\d\+]/g,"");
 return a="+"==a.substr(0,1)?"+"+a.replace(/[^\d]/g,""):a.replace(/[^\d]/g,"")
}

I'm trying to convert this function to PHP and was wondering if this is correct:

function cleanPhone($a) {
 $a = preg_replace('/[^\d\+]/g',"", $a);
 return $a = "+" == substr(0,1)?"+"+ preg_replace('/[^\d]/g',"", $a) : preg_replace('/[^\d]/g',"", $a);
}

• Jay Blanchard: Have you tested it?
• Funk Forty Niner: I did Sam, and got a busy signal - @JayBlanchard
• MB34: yes, I have and got this first: Unknown modifier 'g'

Answer 1

g is not a valid modifier in PCRE (the regex implementation PHP uses) because it's simply not needed; preg_replace() will perform global replacements by default. You'll find the modifier in true Perl regex as well as JavaScript regex, but not in PCRE.

I would write it more clearly:

function cleanPhone($a) {
 $a = preg_replace('/[^\d\+]/', "", $a);
 if(substr($a, 0, 1) == "+"){
 return "+" + preg_replace('/[^\d]/', "", $a); 
 }else{
 return preg_replace('/[^\d]/',"", $a);
 }
}

Also notice you were missing the variable identifier for the substring method substr($string, $startIndex, [$length])

The minified version using a ternary operator should also work:

function cleanPhone($a) {
 $a = preg_replace('/[^\d\+]/',"", $a);
 return ("+" == substr($a,0,1))?"+"+ preg_replace('/[^\d]/',"", $a) : preg_replace('/[^\d]/',"", $a);
}

• MB34: Unknown modifier 'g'
• Patrick Murphy: Check now, you didn't need the g modifier