reduce() is another important method of an array.

reduce()是数组的另一个重要方法。

reduce() executes a callback function on all the items of the array and allows to progressively compute a result. If initialValue is specified, accumulator in the first iteration will equal to that value.

reduce()在数组的所有项目上执行回调函数，并允许逐步计算结果。 如果指定了initialValue ，则第一次迭代中的accumulator将等于该值。

a.reduce((accumulator, currentValue, currentIndex, array) => {  //...}, initialValue)

Example:

例：

[1, 2, 3, 4].reduce((accumulator, currentValue, currentIndex, array) => {  return accumulator * currentValue}, 1)// iteration 1: 1 * 1 => return 1// iteration 2: 1 * 2 => return 2// iteration 3: 2 * 3 => return 6// iteration 4: 6 * 4 => return 24// return value is 24

翻译自: