将foo="get-element-by-id"转换成驼峰表示法 "getElementById"

//将foo="get-element-by-id"转换成getElementById

let foo = "get-element-by-id"
function changName(str) {
    let newArr = str.split('-')
    console.log(newArr);//[ 'get', 'element', 'by', 'id' ]
    for(let i = 1;i<newArr.length;i++){
        newArr[i]=newArr[i].charAt(0).toUpperCase()+newArr[i].substr(1,newArr[i].length-1)
    }
    newArr = newArr.join("")
    return newArr
}
console.log(changName(foo));//getElementById