//数据转换array.map()
let arr = [1,2];
let arr2 = arr.map((x, i, array) => {
  console.log('x', x);
  console.log('i', i);
  console.log('array', array);
  return x * x;
});

//数组聚合array.reduce()
let arr3 = [1,2,3,4,5];
let total = arr3.reduce((x, y) => x + y, 0);
console.log('total', total);

//数组聚合从右到左array.reduceRight()
let arr4 = [2,10,60];
let final = arr4.reduceRight((x,y) => x / y);
console.log('final', final);

const numbers = [1, 2, 3];
const sum = numbers.reduceRight((acc, curr) => acc + curr, 10);
console.log(sum);

const flattened = [[0, 1], [2, 3], [4, 5]].reduceRight((acc, curr) => acc.concat(curr), []);
console.log(flattened);

//数组匹配array.some()
const isOk = arr3.some(x => x > 3);
console.log('isOk', isOk);

//稀疏数组
let arr5 = [1,2,,3];
let aaa = arr5.map(x => x);
console.log(aaa)