CODEWITHSUNDEEP
javascript
ADAMPOKE111
ADAMPOKE111

Reputation: 5

What does this obfuscated javascript snippet mean/do?

I cannot understand what this little snippet: var num = str.replace(/[^0-9]/g, ''); does.

Context:

function retnum(str) {
    var num = str.replace(/[^0-9]/g, '');
    var liczba = parseInt(num);
    return liczba;
}

Upvotes: 0

Views: 76

Answers (4)

David Hariri
David Hariri

Reputation: 989

This JavaScript snippet will rip out anything that is not (the ^ part of the regular expression means "not") a number in str and then return an integer cast from the result as liczba. See my comments:

// This function will return a number from a string that may contain other characters.
// Example: "1.23" -> 123
// Example: "a123" -> 123
// Example: "hg47g*y#" -> 47

function retnum(str) {
    // First let's replace everything in str that is not a number with "" (nothing)
    var num = str.replace(/[^0-9]/g, '');
    // Let's use JavaScript's built in parseInt() to parse an Integer from the remaining string (called "num")
    var liczba = parseInt(num);
    // Let's now return that Integer:
    return liczba;
}

By the way, "liczba" means number in Polish :-)

Upvotes: 2

Dave
Dave

Reputation: 161

It literally just replaces anything which is not a number with a blank ('').

Upvotes: 0

Kate Hedgpeth
Kate Hedgpeth

Reputation: 101

This function takes a string, strips all non-number characters from it, turns the string into an integer, and returns the integer. The line you're asking about specifically is the part that strips out all non-number characters from the initial string, using the string.replace method.

Upvotes: 2

Mike Cluck
Mike Cluck

Reputation: 32511

It's not obfuscated, it's using a regular expression.

The expression matches all things which are not numbers then removes them. 0-9 means "any digit" and the ^ means "not". The g flag means to check the entire string instead of just the first match. Finally, the result is converted to a number.

Example:

var input = 'abc123def456';
var str = input.replace(/[^0-9]/g, '');
var num = parseInt(str);
document.querySelector('pre').innerText = num;
<pre></pre>

Upvotes: 0

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