Split string in JavaScript using regular expression

JavaScript has split() method which returns array of the substrings based on the separator character used. But you can also split a string using regular expression.

Say you have a credit card number which you want to split in array of four substrings with each substring consisting of 4 digits. For that you would use the match method of string.

var strValue = "1111222233334444";
var splitValues = strValue.match(/(\d{4})(\d{4})(\d{4})(\d{4})/);

// Start looping array from 1st index position as 0
// index position contains the entire parent string
for (var i=1 ; i<splitValues.length ; i++) {
 // Loop through the elements
}

Here, you use the match method and pass it the regular expression of (\d{4})(\d{4})(\d{4})(\d{4}) to split it into four equal substrings of four digits each. One thing to remember here is that the string returned here contains the parent string at the 0 index position and then the split substrings start at 1st position.

There is limitation here though — you need to know the number of characters in the string before hand, which might not be the case always.