The split() method in JavaScript is used to divide a string into an array of substrings based on a specified separator. It returns a new array without modifying the original string.

Syntax

string.split(separator, limit)

• separator: The character, string, or regular expression used to determine where to split the string. If omitted or undefined, the entire string is returned as a single-element array.

• limit: An optional integer that specifies the maximum number of substrings to include in the array. If provided, the method stops splitting after reaching this limit.

Key Examples

• Split by space:

  "Hello World".split(" "); // Returns ["Hello", "World"]

• Split by comma:

  "Jan,Feb,Mar".split(","); // Returns ["Jan", "Feb", "Mar"]

• Split by empty string (UTF-16 code units):

  "Hi".split(""); // Returns ["H", "i"]

  ⚠️ Note: Using an empty string as a separator splits by UTF-16 code units, which can break surrogate pairs (e.g., emojis). Use the spread operator [...str] for correct character splitting.

• Limit the number of splits:

  "a b c d".split(" ", 2); // Returns ["a", "b"]

• Using regular expressions:

  "Hello1World2Test".split(/(\d)/); // Returns ["Hello", "1", "World", "2", "Test"]

Special Cases

• If the string is empty and the separator is non-empty, returns [""].

• If both string and separator are empty, returns [].

• If the separator is a regular expression with capturing groups, the captured groups are included in the result array.

For more details, refer to the MDN Web Docs.