What String.substr(negative number) does?

javascript, substr, substring

Solution

`substr()` returns the a string made up of the last `N` characters, when `-N` is passed to it.

`"Hello".substr(-2)` => `"lo"`

From the docs:

If start is negative, substr uses it as a character index from the end of the string. If start is negative and abs(start) is larger than the length of the string, substr uses 0 as the start index.

Problem

I found this snippet, but I am not sure if it should have `-5` or `-6`, because I do not what exactly `substr(negative)` does. ``` ('00000'+(15).toString(16)).substr(-5) ```

Original source