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reduceRight()

Try it​

reduceRight() 方法接受一个函数作为累加器（accumulator）和数组的每个值（从右到左）将其减少为单个值。

const array1 = [
  [0, 1],
  [2, 3],
  [4, 5],
];

const result = array1.reduceRight((accumulator, currentValue) =>
  accumulator.concat(currentValue)
);

console.log(result);
// expected output: Array [4, 5, 2, 3, 0, 1]

Example​

展示 reduce 与 reduceRight 之间的区别​

var a = ["1", "2", "3", "4", "5"];
var left = a.reduce(function (prev, cur) {
  return prev + cur;
});
var right = a.reduceRight(function (prev, cur) {
  return prev + cur;
});

console.log(left); // "12345"
console.log(right); // "54321"