Why the code below returns 1? That doesn't make sense.

var length = "".split(" ").length;
console.log(length);

Why the code below returns 1? That doesn't make sense.

var length = "".split(" ").length;
console.log(length);

• javascript

• 4 Possible duplicate of What does split() returns if the string has no match – Ivar Commented Jul 1, 2018 at 19:52

4 Answers 4

Because split will return original string if there wasn't split char in that string.

like:

"".split(" ")
// [""]
"a".split(" ")
// ["a"]

String.prototype.split()

Note: When the string is empty, split() returns an array containing one empty string, rather than an empty array. If the string and separator are both empty strings, an empty array is returned.

split returns array [""] which length is 1.

split will "break up" the string when a match is found, so:

"something".split("different");

Will not break up the string, resulting in:

["something"]

The same applies to an empty string.

Simply put, it will split the string at every " ", though since the string doesn't have any " ", it will be an array with only one item holding the original string itself, no matter that string is empty or not, hence length is 1.

Below samples shows the length if there were just one " " in the string, ending in ["",""].

console.log( "".split("").length );

console.log( "".split(" ").length );

console.log( " ".split(" ").length );