SOURCE

function toCamelCaseVar( variable ) {
    // write code here
    //console.log("a".charCodeAt(0))
    let a = variable.split('_')
    //console.log(a)
    for(let i = 0;i<a.length;i++){
        let temp = a[i].split('')
        //console.log(temp)
        let kksk = temp[0].charCodeAt(0)
        if(i==0&&kksk>=65&&kksk<=90){
            temp[0] = String.fromCharCode(kksk+32);
        }
        if(i>0&&kksk>=97&&kksk<=122){
            temp[0] = String.fromCharCode(kksk-32);
        }
        for(let j = 1;j<temp.length;j++){
            let u = temp[j].charCodeAt(0)
            if(u>=65&&u<=90){
                temp[j] = String.fromCharCode(u+32);
            }
        }
        //console.log(temp)
        a[i]=temp.join('')
        //console.log(a[i])
    }
    //console.log(a)
    return a.join('')
}
console.log(toCamelCaseVar("PPFoo_IIIstYle_css"))
//console.log("z".charCodeAt(0))