Node.js - String split Examples

Split. Consider a string that has many parts. It has a delimiter character that we want to split upon. With split() in Node.js we have many ways to do this.

Method notes. Often, the best approach is the simplest. With a single character delimiter, we can write simple code to split the string. Sometimes a regular expression is needed.

First example. Here we introduce a string literal that has 4 substring separated with a plus delimiter. The "plus" character separates 4 color names.

Part 1 We call the split method with a one-character string argument: the "+" char.

Part 2 The array returned has 4 strings in it—the plus separates each string so there are fewer delimiters than strings.

Part 3 We loop over the array returned from the split method. It has 4 elements, one string for each color word.

var colors = "blue+orange+red+yellow"; // Part 1: split on the plus. var result = colors.split("+"); // Part 2: write the length. console.log("SPLIT RESULT LENGTH: " + result.length); // Part 3: write each resulting string. for (var i = 0; i < result.length; i++) { console.log("SPLIT RESULT: " + result[i]); }

SPLIT RESULT LENGTH: 4 SPLIT RESULT: blue SPLIT RESULT: orange SPLIT RESULT: red SPLIT RESULT: yellow

Regex. Sometimes we need a more complex approach to separating strings. We can use a regular expression. Here we split on one or more non-word characters (like spaces or newlines).

Tip With a regular expression, we can treat multiple delimiters as a single one. This eliminates empty entries.

var data = "cat bird frog"; // Split on one or more non-word characters. // ... This includes spaces and newlines. var results = data.split(/\W+/); console.log("SPLIT NON-WORD: " + results);

SPLIT NON-WORD: cat,bird,frog

Get numbers. With split() and a regular expression we can get the numbers from a string. We split on non-digit characters. The uppercase "D+" means one or more non-digit chars.

Tip To extract numbers, we can split on "not number" characters. Then we use Number() to convert the strings to actual numeric values.

var input = "0 cat 10(20)30-500"; // Split on no none or more non-digit chars. var numberStrings = input.split(/\D+/); // Convert all strings into Numbers. // ... Write them. for (var i = 0; i < numberStrings.length; i++) { var number = Number(numberStrings[i]); console.log("NUMBER: " + number); }

NUMBER: 0 NUMBER: 10 NUMBER: 20 NUMBER: 30 NUMBER: 500

Character set. We can split on a set of characters—here we have 3 char delimiters, and we split a string on all of them in a single call. We use a character set in the regular expression.

Tip Be careful to escape metacharacters in the regex. If the pattern does not work, try escaping some characters with the backslash.

// This string has multiple delimiter chars. var codes = "100x200y300z400"; // Split on a set of characters at once. var results = codes.split(/[xyz]/); // Display results. for (var i = 0; i < results.length; i++) { console.log("RESULT: " + results[i]); }

RESULT: 100 RESULT: 200 RESULT: 300 RESULT: 400

Splitting a string is a common operation in nearly all languages. When we call Split, we receive an array of the parts that were separated by a delimiter.