JavaScript - How to Check if a String Contains Double Quotes?

Here are the different methods to check if a string contains double quotes.

1. Using includes() Method

The includes() method is the simplest way to check if a string contains a specific substring, including double quotes. This method returns true if the substring is found and false otherwise.

let s = 'Hello "world"!';
let res = s.includes('"');
console.log(res);

true

• includes('"') checks if the double quote (") is present in the string.
• This method is case-sensitive and works for checking a single character or substring.
• It returns a boolean value (true or false), making it very easy to use for this purpose.

2. Using indexOf() Method

The indexOf() method can also be used to check for the presence of double quotes. It searches for the first occurrence of a specified substring and returns its index. If the substring is not found, it returns -1.

let s = 'Hello "world"!';
let res = s.indexOf('"') !== -1;
console.log(res);

true

• indexOf('"') returns the index of the first occurrence of a double quote in the string.
• If the index is -1, the string does not contain the double quote.
• This method is useful if you also want the index of the first occurrence of the double quote in the string.

3. Using Regular Expressions (RegExp)

Regular expressions provide a flexible way to check for the presence of characters in a string. You can use the RegExp object to check if a string contains double quotes.

let s = 'Hello "world"!';
let res = /"/.test(s);
console.log(res);

• The regular expression /"/ looks for the double quote character in the string.
• test() is a method that returns true if the regular expression matches any part of the string.
• This method is useful if you need to perform more complex pattern matching, such as checking for double quotes surrounded by specific characters.

4. Using match() Method

The match() method can be used with regular expressions to check if a string contains double quotes. This method returns an array of all matches or null if no match is found.

let s = 'Hello "world"!';
let res = s.match(/"/) !== null;
console.log(res);

true

• match(/"/) searches for all occurrences of double quotes in the string.
• If no match is found, it returns null. If matches are found, it returns an array of matched values.
• You can compare the result to null to check if the double quote is present in the string.

5. Using split() Method

The split() method can be used to split the string into an array of substrings. You can then check if the array length is greater than one, which would indicate the presence of the double quote.

let s = 'Hello "world"!';
let res = s.split('"').length > 1;
console.log(res);

true

• split('"') splits the string into an array wherever a double quote occurs.
• If the length of the resulting array is greater than 1, it means there is at least one double quote in the string.
• This method can be used to detect multiple occurrences of double quotes as well.

Which Approach to Choose?