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 — user10972884
– user10972884, Commented Jun 27, 2019 at 15:22

Community · Accepted Answer · 2020-06-20 09:12:55Z

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('')]);

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answered Jun 27, 2019 at 15:14

Maheer Ali

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5 Comments

can you let me know in my code when array is converted to string

@zizi Whenever you apply + operator b/w two arrays. Arrays will be converted to a string .

hey in spread operator can you let me know why its printing in next line?

@zizi It doesn't matter. If you use the normal console it will work fine. Also its an array not a string.

hey when I give comma inside an array, can you tell me why I am getting undefined :(