Check if a String contains Spaces in JavaScript

# Table of Contents

1. Check if a String contains only Spaces in JavaScript
2. Check if String contains any Whitespace in JavaScript

# Check if a String contains only Spaces in JavaScript

To check if a string contains only spaces:

1. Use the String.trim() method to remove the leading and trailing whitespace from the string.
2. Check if the length of the string is 0.
3. If the condition is met, the string contains only spaces.

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function containsOnlySpaces(str) {
  return str.trim().length === 0;
}

console.log(containsOnlySpaces('   ')); // 👉️ true
console.log(containsOnlySpaces('  123  ')); // 👉️ false
console.log(containsOnlySpaces('bobbyhadz.com ')); // 👉️ false
console.log(containsOnlySpaces('')); // 👉️ true

If you need to check if a string contains any whitespace, click on the following subheading.

• Check if String contains any Whitespace in JavaScript

The String.trim() method removes the whitespace characters from both ends of a string.

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console.dir(' bobby  '.trim()); // 👉️ 'bobby'

console.dir('    '.trim()); // 👉️ ''

We check if the result of calling the method on the string returns a string of length 0.

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console.dir(' bobby  '.trim().length); // 👉️ 5

console.dir('    '.trim().length); // 👉️ 0

If it does, we either have a string that contains only spaces or an empty string.

An alternative, but also very common approach is to use a regular expression.

# Check if a String contains only spaces using RegExp.test()

You can also use the RegExp.test() method.

The test() method will return true if the string contains only spaces and false otherwise.

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function containsOnlySpaces(str) {
  return /^\s*$/.test(str);
}

console.log(containsOnlySpaces('   ')); // 👉️ true
console.log(containsOnlySpaces('  123  ')); // 👉️ false
console.log(containsOnlySpaces('bobbyhadz.com ')); // 👉️ false
console.log(containsOnlySpaces('')); // 👉️ true

We used the RegExp.test() method to check if a string contains only spaces.

The forward slashes / / mark the beginning and end of the regular expression.

The caret ^ matches the beginning of the input and the dollar sign $ matches the end of the input.

The asterisk * character matches the preceding item (space) 0 or more times.

If you ever need help reading a regular expression, check out this regular expression cheat sheet by MDN.

It contains a table with the name and the meaning of each special character with examples.

# Check if a String contains only spaces using String.match()

Alternatively, you can use the String.match() method.

The expression will return true if the string contains only spaces and false otherwise.

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function containsOnlySpaces(str) {
  return str.match(/^\s*$/) !== null;
}

console.log(containsOnlySpaces('   ')); // 👉️ true
console.log(containsOnlySpaces('  123  ')); // 👉️ false
console.log(containsOnlySpaces('bobbyhadz.com ')); // 👉️ false
console.log(containsOnlySpaces('')); // 👉️ true

The String.match() method returns the result of matching a string against a regular expression.

The method returns an array containing the matches (if any) or null if no matches are found.

We compared the output of the method to null to get a boolean result.

Which approach you pick is a matter of personal preference. I'd go with the trim() method as I find it easier to read and more beginner-friendly.

# Check if String contains Whitespace in JavaScript

Use the test() method to check if a string contains whitespace.

The test method will return true if the string contains at least one whitespace character and false otherwise.

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function containsWhitespace(str) {
  return /\s/.test(str);
}

console.log(containsWhitespace('  ')); // 👉️ true
console.log(containsWhitespace('bobby hadz com')); // 👉️ true
console.log(containsWhitespace('')); // 👉️ false
console.log(containsWhitespace('test')); // 👉️ false

We used the RegExp.test() method to check if a string contains whitespace.

The test() method returns true if the regular expression is matched in the string and false otherwise.

The forward slashes / / mark the start and end of the regular expression.

Our regular expression checks for all types of whitespace characters, including tabs \t and newline characters \n.

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function containsWhitespace(str) {
  return /\s/.test(str);
}

console.log(containsWhitespace('hello\tworld')); // 👉️ true
console.log(containsWhitespace('hello\nworld')); // 👉️ true

if (containsWhitespace('hello\nworld')) {
  // 👇️ this runs
  console.log('The string contains whitespace');
} else {
  console.log('The string does NOT contain whitespace');
}

# Check if String contains Whitespace using String.includes()

If you only want to check if the string contains spaces, use the String.includes() method.

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function containsWhitespace(str) {
  return str.includes(' ');
}

console.log(containsWhitespace('  ')); // 👉️ true
console.log(containsWhitespace('bobby hadz com')); // 👉️ true
console.log(containsWhitespace('')); // 👉️ false
console.log(containsWhitespace('test')); // 👉️ false

Note that the includes() method doesn't check for all types of whitespace, it checks only for spaces.

The String.includes() method returns true if the supplied substring is contained in the string and false otherwise.

The includes() method would return false if your string contains only tabs \t or newline characters \n.

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function containsWhitespace(str) {
  return str.includes(' ');
}

console.log(containsWhitespace('bobby hadz')); // 👉️ true
console.log(containsWhitespace('hello\tworld')); // 👉️ false
console.log(containsWhitespace('hello\nworld')); // 👉️ false

If you also want to test for tabs and newline characters, use the regex approach.

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function containsWhitespace(str) {
  return /\s/.test(str);
}

console.log(containsWhitespace('hello\tworld')); // 👉️ true
console.log(containsWhitespace('hello\nworld')); // 👉️ true

# Check if a string contains whitespace using String.match

You can also use the String.match() method to check if a string contains whitespace.

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function containsWhitespace(str) {
  return str.match(/\s/) !== null;
}

console.log(containsWhitespace('bobby hadz')); // 👉️ true
console.log(containsWhitespace('hello\tworld')); // 👉️ true
console.log(containsWhitespace('hello\nworld')); // 👉️ true
console.log(containsWhitespace('bobbyhadz.com')); // 👉️ false

The String.match() method returns the result of matching a string against a regular expression.

The method returns an array containing the matches (if any) or null if no matches are found.

We compared the output of the method to null to get a boolean result.

Which approach you pick is a matter of personal preference. I'd go with the RegExp.test() method because I find it more direct and intuitive.

If you ever need help reading a regular expression, check out this regular expression cheat sheet by MDN.

It contains a table with the name and the meaning of each special character with examples.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• Check if a String contains Numbers in JavaScript
• Check if String contains only Letters and Numbers in JS
• Check if String contains Special Characters in JavaScript
• Zip Code (US Postal Code) validation in JavaScript