I didn't know about the wanted '==' typed '=' mistake. You can find the left-constant comparison useful in coffee-script too! Although in different scenario as in coffee-script the compare operation is done with the is keyword.
In JS I would write
indexOf(item) === 1;
naively in CS I might try
indexOf item is 1
but the compiled JS is
indexOf(item === 1); // oops
so the correct code is:
indexOf(item) is 1
and finally, to avoid the parentheses I settled with the pattern
1 is indexOf item
which produces
1 === indexOf(item);
Nice to know that it's called Yoda conditions.