JavaScript String split() Method

What You’ll Learn

String.prototype.split() divides a string into an array of substrings by searching for a separator pattern (same API as MDN String.prototype.split()). Learn string and regex separators, the optional limit, capturing groups, empty edges, five examples, and try-it labs.

Introduction

Need words from a sentence, columns from a CSV line, or path segments from a URL? split() cuts the string wherever a separator matches and returns an array of the pieces.

The separator can be a string (like " " or ",") or a regular expression. An optional limit stops after a fixed number of pieces. The original string never changes.

This page is part of JavaScript String Methods. Related topics include slice() and search().

Understanding the split() Method

str.split(separator, limit) searches for separator and builds an ordered array of the text between matches. The separator itself is usually left out (unless a regex capturing group pulls parts of it back in).

• Returns a new array; the original string is unchanged.
• Omit separator to get a one-element array with the whole string.
• Use "" to split into individual code units (see Unicode note below).
• Use limit when you only need the first few pieces.

📝 Syntax

General form of String.prototype.split:

str.split(separator)
str.split(separator, limit)

Parameters

• separator — where to cut. A string, a RegExp, or an object with Symbol.split. Omit / pass undefined to return [str]. Other values are coerced to strings.
• limit (optional) — non-negative integer capping how many substrings to include. Leftover text is discarded. 0 returns [].

Return value

An Array of strings (regex capturing groups may also insert matched pieces):

Common patterns

"a,b,c".split(",");     // ["a", "b", "c"]
"one two".split(" ");   // ["one", "two"]
"hello".split("");      // ["h", "e", "l", "l", "o"]
"keep whole".split();   // ["keep whole"]
"a-b-c-d".split("-", 2); // ["a", "b"]

Examples Gallery

Examples follow MDN String.split() patterns. Use View Output or Try It Yourself for each case.

const str = "The quick brown fox jumps over the lazy dog.";

const words = str.split(" ");
words[3];
// "fox"

const chars = str.split("");
chars[8];
// "k"

const strCopy = str.split();
// ["The quick brown fox jumps over the lazy dog."]

fox
k
["The quick brown fox jumps over the lazy dog."]

const monthString = "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec";
monthString.split(",");
// 12 month abbreviations

"".split("a");  // [""]  — empty string, non-empty separator
"".split("");   // []    — both empty

"a,,c".split(",");
// ["a", "", "c"]  — consecutive separators create empty pieces

["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"]
[""]
[]
["a","","c"]

const myString = "Hello World. How are you doing?";
myString.split(" ", 3);
// ["Hello", "World.", "How"]

"a-b-c-d".split("-", 0);
// []

"a-b-c-d".split("-", 1);
// ["a"]

["Hello","World.","How"]
[]
["a"]

const names = "Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand ";
names.split(/\s*(?:;|$)\s*/);
// ["Harry Trump", "Fred Barney", "Helen Rigby", "Bill Abel", "Chris Hand", ""]

const myString = "Hello 1 word. Sentence number 2.";
myString.split(/(\d)/);
// ["Hello ", "1", " word. Sentence number ", "2", "."]

["Harry Trump","Fred Barney","Helen Rigby","Bill Abel","Chris Hand",""]
["Hello ","1"," word. Sentence number ","2","."]

function fileName(path) {
  const parts = path.split("/");
  return parts[parts.length - 1];
}

function domainOf(email) {
  return email.split("@")[1];
}

fileName("views/js/string/methods/split.ejs");
// "split.ejs"

domainOf("hello@codetofun.com");
// "codetofun.com"

["a", "b", "c"].join("-");
// "a-b-c"

split.ejs
codetofun.com
a-b-c

🚀 Common Use Cases

• Tokenize text — words, tags, or CSV columns.
• Parse paths / URLs — split on / or ?.
• Read config lines — cut key/value pairs on = or :.
• Take a prefix of tokens — use the limit argument.
• Not for index windows — use slice() when you know start/end indexes.
• Not for emoji-safe chars — prefer Array.from(str) over split("") for Unicode code points.

📝 Notes

• The separator is usually not included in the result (except regex capturing groups).
• split("") splits UTF-16 code units — emoji may break into surrogates.
• Leading/trailing separators create empty strings at the ends of the array.
• limit discards leftover text; it does not append a “remainder” piece.
• Pair with join() to rebuild a string from pieces.
• Always capture the returned array — the original string is unchanged.

💡 Best Practices