Simple ascii replacement - Javascript

Question

I'm looking for a javascript function which takes a string parameter and checks for ascii characters lower than 32, replacing them with empty string -> "". I'm new to javascript so I was wondering whether anyone can point me towards the right direction ?

Thanks in advance for your time.

• Prof. Falken: Also, why? Might be a better way.
• Ferhat: stackoverflow.com/questions/94037/… this may help
• Pumpkin: What I meant was, I want to find and remove any characters within the string that has a lower ascii value than 32

Answer 1

Try this:

var replaced = string.replaceAll("[^ -~]", "");

Using ^ negates the characters class, and since space is character 32 in the ASCII table and ~ is the last printable character, you're basically saying "everything that isn't a printable character".

To simply remove all characters from 0-31 use:

var replace = string.replaceAll("\x00-\x1F", "");

• Sean Airey: See my edit, I've included how to match specific character codes, with 1F being 31.
• Vitaly Zdanevich: This will remove french letter à.
• Sean Airey: @Vitaly Not at desk ATM, which code is à? You could just add "^à" or "^{insert character code here}" to the regular expression to get it to exclude those from the replacement :)

Answer 2

If I understand your question correctly you are looking for a regex to use with .replace...

For replacing any printable ascii chars you can use this regex:

/[ -~]/

You will probably have to adjust the range. I recommend changing the tilder since it is the last printable char.

Sorry, I see what you mean! I think you cannot match unprintable chars unless use use their special symbol: i.e. \b \s \n etc.

Answer 3

function keepCharsAbove(inStr, charCode) {
 var goodChars = [];
 for(var x = 0; x < inStr.length; x++) {
 if(inStr.charCodeAt(x) > charCode) {
 goodChars.push(inStr.charAt(x));
 }
 }
 return goodChars.join("");
}

​ Usage:

keepCharsAbove("foo \t bar",32); // returns 'foobar'

• Richard: This would probably be better by converting the input to an array of single character strings, filtering the array (Array.filter) and then joining back into a string. (A more functional approach.)