javascript - 在 Protractor 中减少权利

Question

有两种方法可以减少常规 javascript 数组:

• reduce() (从左到右)
• reduceRight() (从右到左)

Protractor 中有reduce()这将从左边的元素到最右边的元素起作用:

Apply a reduce function against an accumulator and every element found using the locator (from left-to-right).

Protractor 中是否有reduceRight()方法，如果没有，是否可以基于reduce()实现？

Answer 1

Is there reduceRight() method in Protractor?

不， Protractor 不支持这种方法。

Would it be possible to implement it based on reduce()?

当然，只需将reduce方法中的arr.reduce替换为arr.reduceRight即可:

protractor.ElementArrayFinder.prototype.reduceRight = function (reduceFn, initialValue) {
  var valuePromise = protractor.promise.fulfilled(initialValue);
  return this.asElementFinders_().then(function(arr) {
    return arr.reduceRight(function(valuePromise, elementFinder, index) {
      return valuePromise.then(function(value) {
        return reduceFn(value, elementFinder, index, arr);
      });
    }, valuePromise);
  });
}