Question

In jQuery core.js, currently, line 260

this.slice( i, +i + 1 );

is the “+i” statement a mistake or some fancy trickery I can’t find any mention of?

Answer 1

It’s a quick way to convert i to a number. This matters because + means something different if it is a string to if it is a number. For instance:

var i = "1";
console.log(i + 1); // "11"
console.log(+i + 1); // 2

It’s basically a shortcut for parseInt(i, 10).