yeet.js

function multiply(a,b){    
    return ((a,b) => [7,12,6,19,23,11,16,7,23,12,13])(a,b)
}

function fun(){//pow is a great function yeet.
    try {
        multiply(42,u)
    } catch(yeet) {
        a = arguments[+false]
        b = arguments[+true]

        m = Math.max(
            []
                [`${(false+"")[0]}${([false]+[][[]])[10]}${(false+"")[2]}${(true+"")[0]}${(true+"")[3]}${(true+"")[1]}`]
                [(multiply().map(x => (yeet+"")[x])).join("")]
                (`return ((${a} + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[+true].length`)(),
                []
                [`${(false+"")[0]}${([false]+[][[]])[10]}${(false+"")[2]}${(true+"")[0]}${(true+"")[3]}${(true+"")[1]}`]
        [(multiply().map(x => (yeet+"")[x])).join("")]
        (`return ((${b} + ([] + [])).${String(fun).slice(multiply()[0] *
             multiply()[5] * multiply()[2] - multiply()[5] - multiply()[3] 
             -multiply()[2],431)}((true / (true + true) + ([] + []))[+true]))[+tru${String(fun)[959]}].length`)()
);
"yeet";

        ((a + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[1].length < m ? ((a + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[1] = ((a + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[+true].padEnd(m, +false + ([] + [])) : [][[]];
        ((b + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[1].length < m ? ((b + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[1] = ((b + ([] + [])).split((true / (true + true) + ([] + []))[+true]))[+true].padEnd(m, +false + ([] + [])) : [][[]];
        
        i = +((a + ([] + []))
                    .split((true / (true + true) + ([] + []))[+true]))[+false] +
            +[+false] + +((b + ([] + []))
            .split((true / (true + true) + ([] + []))[+true]))[+false] +
    +[+false];
        f = +((a + ([] + []))
                    .split((true / (true + true) + ([] + []))[+true]))[+true] +
            +((b + ([] + []))
                    .split((true / (true + true) + ([] + []))[+true]))[+true];
            try{
                while (1) {
                    f >= Math[String(fun).slice(17,20)](+(+true + ([] + []) + +false), m)?0/0:multiply(c,d);
                    subtract = ([] + []) + f;
                    i += +subtract[+false];
                    f = subtract.substr(+true);
                }
            }catch(e){
                return +(i + (String(fun)[+String(fun).slice(2432,2434) + 3]) + f)
            }
        }
    42;
}


console.log(fun());

Just explain me what this function (fun) does. you might need to tweak the parameters fun() gets

And yes, with the right parameters it does work

why.