split method and array concatenation js

Question

to understand the split method I went over this link https://www.w3schools.com/jsref/jsref_split.asp
but not sure why comma not adding after 3 and why empty array not showing up in the output
is it just doing array concatenation
i debugged but not sure
can you guys let me know.

[123] + [] + 'foo'.split('');
"123f,o,o"

@epascarello hey I am trying to learn concatenation and split operations — , Jun 27 '19 at 15:22
https://stackoverflow.com/questions/7124884/why-is-1-2-3-4-1-23-4-in-javascript — User863, Jun 27 '19 at 15:24

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

2

When the array is converted to string. Implicitly join() is called on it. So [].join() is '' that's why it doesn't show up in string.

But if you use some empty elements then it will show ,

console.log([123] + [,] + 'foo'.split(''));

There can be different ways to concat two or more arrays. The modern one is using Spread Operator.

console.log([...[123], ...[],...'foo'.split('')]);

edited Jun 20 '20 at 09:12

Community

answered Jun 27 '19 at 15:14

Maheer Ali

can you let me know in my code `when array is converted to string` – Jun 27 '19 at 15:21
@zizi Whenever you apply `+` operator b/w two arrays. Arrays will be converted to a string . – Maheer Ali Jun 27 '19 at 15:24
hey in spread operator can you let me know why its printing in next line? – Jun 27 '19 at 18:19
@zizi It doesn't matter. If you use the normal console it will work fine. Also its an array not a string. – Maheer Ali Jun 28 '19 at 09:02
hey when I give comma inside an array, can you tell me why I am getting undefined :( – Jun 28 '19 at 13:43

1 Answers1