Replacing Spaces with Underscores in JavaScript

Replacing spaces with underscores in JavaScript?

Try .replace(/ /g,"_");

Edit: or .split(' ').join('_') if you have an aversion to REs

Edit: John Resig said:

If you're searching and replacing
through a string with a static search
and a static replace it's faster to
perform the action with
.split("match").join("replace") -
which seems counter-intuitive but it
manages to work that way in most
modern browsers. (There are changes
going in place to grossly improve the
performance of .replace(/match/g,
"replace") in the next version of
Firefox - so the previous statement
won't be the case for long.)

Replace initial spaces with underscores in Javascript

I want to replace each of the leading spaces with an underscore

To do that with just one replace call within the current spec,* you'd need the function call version of replace to do that, creating a string of underscores as long as the matched sequence of spaces:

y = x.replace(/^ +/, function(m) {
    return "_".repeat(m.length);
});

or with an ES2015+ arrow function:

y = x.replace(/^ +/, m => "_".repeat(m.length));

Live Example:

const x = "    four spaces";const y = x.replace(/^ +/, m => "_".repeat(m.length));console.log(y);

How to replace all spaces in a string

var result = replaceSpace.replace(/ /g, ";");

Here, / /g is a regex (regular expression). The flag g means global. It causes all matches to be replaced.

How to replace underscores with spaces?

You can replace all underscores in a string with a space like so:

str.replace(/_/g, ' ');

So just do that before the content is put in. If you need to perform the replacement afterwards, loop using each:

$('.name').each(function () {
    this.textContent = this.textContent.replace(/_/g, ' ');
});

Replace spaces with dashes and make all letters lower-case

Just use the String replace and toLowerCase methods, for example:

var str = "Sonic Free Games";
str = str.replace(/\s+/g, '-').toLowerCase();
console.log(str); // "sonic-free-games"

Notice the g flag on the RegExp, it will make the replacement globally within the string, if it's not used, only the first occurrence will be replaced, and also, that RegExp will match one or more white-space characters.

Replace commas, full stops, hyphens, and spaces with underscore

You need to escape the - character, because it's used to specify a range of characters like 0-9 or a-z.

console.log('Helo,._cool '.replace(/[,.\- ]/g, "_"));

How can I regex replace all spaces in matched text with underscore? (Javascript)

Use a function in the replace() method. That function can perform a nested replacement on that capture group.

let str = `enum class test{    something1, // this is a comment    something2, // something else    something3,};`;
let new_str = str.replace(/\,.*\/\/\s*(.*)/g, (match0, match1) => ' | ' + match1.replace(/ /g, '_'));console.log(new_str);

change spaces entered in input field to underscore in real time

You may listen to the input event and then replace the spaces with underscores in the listener. This way, you don't need to have a timeout.

$("#inputId").on('input', function(key) {  var value = $(this).val();  $(this).val(value.replace(/ /g, '_'));})

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script><input type="text" id="inputId">

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