JS: Replace whitespace with character

Question

I'm trying to figure out how to replace all the whitespaces with a character given. My code is duplicating the character when the whitespace is replaced.

This is the exercise, and my code so far:

This function receives a string. It also takes an optional character, which should default to an underscore ('_') when not given.

It should return the same string, but with all groups of whitespace (spaces, tabs and line breaks) replaced by a single instance of the character in the second argument.

function replaceWhitespaceWithCharacter (str, character) {
  return str.replace(/\s/g, character);
}

Also, I don't know how to default the underscore. Could anyone give me a hand, please? Thank you in advance.

*"Also, I don't know how to default the underscore"* Best to ask **one** question/question, and also be sure to [search thoroughly](/help/searching) as the topic of how to default parameter values is very well-covered on SO (and elsewhere). — T.J. Crowder, Mar 24 '18 at 12:54

score 4 · Accepted Answer · answered Mar 24 '18 at 12:51

/\s/g matches one character of whitespace (repeatedly). To match one or more characters of whitespace in a row, use + after \s: /\s+/g.

function replaceWhitespaceWithCharacter (str, character) {
  return str.replace(/\s+/g, character);
}

Also, I don't know how to default the underscore

Before ES2015, you'd do something like this:

function replaceWhitespaceWithCharacter (str, character) {
  character = character || "_";
  return str.replace(/\s+/g, character);
}

...because character will be undefined if not given, which is falsy. Or if you want to allow for "" (which is also falsy), then:

function replaceWhitespaceWithCharacter (str, character) {
  character = typeof character === "undefined" ? "_" : character;
  return str.replace(/\s+/g, character);
}

As of ES2015, you can use a default parameter value:

function replaceWhitespaceWithCharacter (str, character = "_") {
  return str.replace(/\s+/g, character);
}

score 1 · Answer 2 · answered Mar 24 '18 at 12:51

1

To include multiple white spaces you should add + like:/\s+/g

So your code should be:

function replaceWhitespaceWithCharacter (str, character) {
  return str.replace(/\s+/g, character);
}

answered Mar 24 '18 at 12:51

Mamun

66,969
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Mr.Pandya · Answer 3 · 2018-03-24T13:01:20.017

1

In regular expression one or more matches. So /\s+/ means white spaces least one max any. Then I am checking whether character is defined or not with ternary operator. If it is not then i am assigning _.

function replaceWhitespaceWithCharacter (str, character) {
  return str.replace(/\s+/g, character?character: '_');
}

edited Mar 24 '18 at 13:01

answered Mar 24 '18 at 12:53

Mr.Pandya

1,899
1
13
24

score 1 · Answer 4 · answered Mar 24 '18 at 13:01

Defaulting to '_', insert :

var chr = (typeof chr !== 'undefined') ? chr : '_';

Replacing groups of white spaces with one or more elements in the group (but not zero) :

  return str.replace(/\s+/g, chr);

So we end up with :

function replaceWhitespaceWithCharacter (str, chr) {
  var chr = (typeof chr !== 'undefined') ? chr : '_';
  return str.replace(/\s+/g, chr);
}

score 0 · Answer 5 · answered Mar 24 '18 at 13:06

You can also extend the string object with the method:

String.prototype.replaceWhitespaceWithCharacter = function replaceWhitespaceWithCharacter(theCharacter) 
{
    if ((typeof theCharacter !== 'string') || (theCharacter === ''))
    {
        theCharacter = '_';
    }
    return this.replace(/\s+/g, theCharacter);
}

My checkings for the character based on typeof for string or if theCharacter is a empty string

score -1 · Answer 6 · answered Mar 24 '18 at 13:00

-1

var str = "this is  a\ttest\n2";
var str2 = str.replace(/\s+/g,'_');

console.log(str2);

this is replace all white spaces with a single underscore.

answered Mar 24 '18 at 13:00

Akarsh Sachdeva

37
2

score -2 · Answer 7 · answered Mar 24 '18 at 12:55

This is my final solution. Thanks for your help.

function replaceWhitespaceWithCharacter (str, character) {

       if(character){
        return str.replace(/\s+/g, character);
       }else{
         return str.replace(/\s+/g, '_');
       }
    }

JS: Replace whitespace with character

7 Answers7