allow only letters, numbers, and spaces. replace repeated spaces with single space

Question

I´m replacing weird characters with "" but I have two scenarios that are not covered.

strings can contain multiple spaces (only one should be allowed) and underscore (, _)

"this_is_my_string".replace(/[^\w\s]/gi, "");

how to tweak it to cover those scenarios?

examples

this_is_my_string => thisismystring
this is my string => this is my string
this     is     my string => this is my string

Answer 1

I think what you really want is this regex:

    value.replace(/_|[^\w\s*]|\s{1,}/g,"");

The _| any character that matches _ [OR] [^ (Negated nest): will match any character that not in the set which is: \w\s* word, whitespace, 0 or more instances of the preceding regex token. ]| exiting the negated nest. [OR] \s{2} , 2 white spaces

Answer 2

 var test = [ 'this_is_my_string', 'this is my string', 'this is my string', 'this%$is my@@@string', ]; console.log(test.map(function(a) { return a.replace(/(\s)+|[\W_]/g, "$1"); }));

Demo & explanation

Answer 3

you could try being more specific with the words part and instead match on the characters, the for the spacing you could just look for more than one space.

[^A-Za-z\s]|\s{2,}

Answer 4

You can try this regex:

/[ \t]{2,}|[\_]/

It will select two or more spaces and underscores.