SOURCE

// for of 练习 
for(let  V of ['a','b','c'] ){
  console.log(V)
}

for(let i  of ['a','b','c'].keys() ){
  console.log(i)
}

for(let v of ['a','b','c'].values() ){
  console.log(v)
}

for(let [i,v]  of ['a','b','c'].entries() ){
  console.log(i,v)
}