数组的方法arr.includes()arr.every(fn(val,i))arr.some(fn(val,i))arr.filter(fn(val,i))arr.map(fn(val,i))ar.reduce(fn(prev,current),initValue)arr.sort()或arr.sort(fn(a,b)) arr.forEach(fn(val,i)) arr.copyWithin(target,start,end) arr.fill(target,start,end) 1.ar…