JavaScript String.match() Method

1. Syntax of JavaScript string.match():
2. Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression
3. Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression Flag -g
4. Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression Flag -g and -i

In JavaScript, the string.match() method is used to find the matched values from a string. This method expects a regular expression as a parameter and returns the result in an array.

This method returns the first match if no parameter is passed.

Syntax of JavaScript string.match():

string.match(regExp)

Parameter

Return

An array of matched results against the regular expression will be returned. If no such value matches, it will produce a null.

Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression

let string = 'Your guess is As good as mine'

console.log(string.match(/as/))

Output:

[
  'as',
  index: 22,
  input: 'Your guess is As good as mine',
  groups: undefined
]

We provided as to the string.match() method and used regular expression. In the string, two values are matched with as, but one is in uppercase, and the other is in lowercase.

It matched with the lowercase and returned the result.

Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression Flag -g

let string = 'Your guess is As good as mine'

console.log(string.match(/as/g))

Output:

[ 'as' ]

In the regular expression, the flag -g refers to the global. When we used it in the string.match() method, it should return all the values that matched with as.

In this case, we should get two as, but we only got one because of case sensitivity. To get all the values, we need to use another flag, -i along with -g.

Example Codes: Use the string.match() Method to Find a Match Value With Regular Expression Flag -g and -i

let string = 'Your guess is As good as mine'

console.log(string.match(/as/gi))

Output:

[ 'As', 'as' ]

In the regular expression, the flag -i refers to case insensitivity. We used this flag along with the global flag; as a result, the global flag returned an array with all matched values of as.