Detect if string contains any spaces

Question

How do I detect if a string has any whitespace characters?

The below only detects actual space characters. I need to check for any kind of whitespace.

Answer 1

What you have will find a space anywhere in the string, not just between words.

If you want to find any kind of whitespace, you can use this, which uses a regular expression:

if (/\s/.test(str)) {
    // It has any kind of whitespace
}

\s means "any whitespace character" (spaces, tabs, vertical tabs, formfeeds, line breaks, etc.), and will find that character anywhere in the string.

According to MDN, \s is equivalent to: [ \f\n\r\t\v​\u00a0\u1680​\u180e\u2000​\u2001\u2002​\u2003\u2004​\u2005\u2006​\u2007\u2008​\u2009\u200a​\u2028\u2029​​\u202f\u205f​\u3000].

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For some reason, I originally read your question as "How do I see if a string contains only spaces?" and so I answered with the below. But as @CrazyTrain points out, that's not what the question says. I'll leave it, though, just in case...

If you mean literally spaces, a regex can do it:

if (/^ *$/.test(str)) {
    // It has only spaces, or is empty
}

That says: Match the beginning of the string (^) followed by zero or more space characters followed by the end of the string ($). Change the * to a + if you don't want to match an empty string.

If you mean whitespace as a general concept:

if (/^\s*$/.test(str)) {
    // It has only whitespace
}

That uses \s (whitespace) rather than the space, but is otherwise the same. (And again, change * to + if you don't want to match an empty string.)