String.prototype.split()

The split() method takes a pattern and divides a String into an ordered list of substrings by searching for the pattern, puts these substrings into an array, and returns the array.

Syntax

split()
split(separator)
split(separator, limit)

Parameters

• separator optional
  • : The pattern describing where each split should occur. Can be a string or an object with a Symbol.split method — the typical example being a regular expression. If undefined, the original target string is returned wrapped in an array.
• limit optional
  • : A non-negative integer specifying a limit on the number of substrings to be included in the array. If provided, splits the string at each occurrence of the specified separator, but stops when limit entries have been placed in the array. Any leftover text is not included in the array at all.
    • The array may contain fewer entries than limit if the end of the string is reached before the limit is reached.
    • If limit is 0, [] is returned.

Return value

An Array of strings, split at each point where the separator occurs in the given string.

Description

If separator is a non-empty string, the target string is split by all matches of the separator without including separator in the results. For example, a string containing tab separated values (TSV) could be parsed by passing a tab character as the separator, like myString.split("\t"). If separator contains multiple characters, that entire character sequence must be found in order to split. If separator appears at the beginning (or end) of the string, it still has the effect of splitting, resulting in an empty (i.e. zero length) string appearing at the first (or last) position of the returned array. If separator does not occur in str, the returned array contains one element consisting of the entire string.

If separator is an empty string (""), str is converted to an array of each of its UTF-16 "characters", without empty strings on either ends of the resulting string.

Note: "".split("") is therefore the only way to produce an empty array when a string is passed as separator.

Warning: When the empty string ("") is used as a separator, the string is not split by user-perceived characters (grapheme clusters) or unicode characters (codepoints), but by UTF-16 codeunits. This destroys surrogate pairs. See "How do you get a string to a character array in JavaScript?" on StackOverflow.

If separator is a regexp that matches empty strings, whether the match is split by UTF-16 code units or Unicode codepoints depends on if the u flag is set.

"😄😄".split(/(?:)/); // [ "\ud83d", "\ude04", "\ud83d", "\ude04" ]
"😄😄".split(/(?:)/u); // [ "😄", "😄" ]

If separator is a regular expression with capturing groups, then each time separator matches, the captured groups (including any undefined results) are spliced into the output array. This behavior is specified by the regexp's Symbol.split method.

If separator is an object with a Symbol.split method, that method is called with the target string and limit as arguments, and this set to the object. Its return value becomes the return value of split.

Any other value will be coerced to a string before being used as separator.