IntelliJ-IdeaVim/doc/ideajoin-examples.md

Some examples of join command with ideajoin option enabled.
Put set ideajoin to your ~/.ideavimrc to enable this functionality.

1. Automatic join concatenated lines:

"Hello" +                 ->       "Hello world"
" world!"

2. Nested if's:

if (a) {                  ->       if (a && b) {
  if (b) {                             ...
     ...                           }
  }
}

3. Remove braces from one line for / if / while:

if (fail) {               ->       if (fail) return;
     return;
}

4. Kotlin one line method:

fun myNumber(): Int {     ->       fun myNumber(): Int = 42
    return 42
}

5. Join declaration and initialization:

int a;                    ->       int a = 5;
a = 5;

6. Chain call:

sb.append("a");           ->       sb.append("a").append("b");
sb.append("b");

And other functions provided by the plugins.