Question

类型错误：无法读取 null 的属性“length”

2016-07-06

4483

javascript

我应该编写一个函数来从字符串中删除元音。我收到一条有关空值的错误消息。经过多次尝试修复后，消息仍然相同，但我尝试过滤空值。

TypeError: Cannot read property 'length' of null at getCount at Test.it at Test.describe at Object.exports.runInThisContext

function getCount(str) {
  var vowelsCount = 0;

  if (str && str.length){
    vowelsCount=str.match(/[aeiou]/gi).length;
  } else {
    vowelsCount=0;
  }

  return vowelsCount;
}

describe("Case 1", function(){
    it ("should be defined", function(){
        Test.assertEquals(getCount("abracadabra"), 5)
    });
});

Answer 1

也许像这样？

function getCount(str) {
  var vowelsCount = 0;

  if (str && str.length){
    var m = str.match(/[aeiou]/gi)
    if (m) return m.length;
  } else {
    vowelsCount=0;
  }

  return vowelsCount;
}

describe("Case 1", function(){
    it ("should be defined", function(){
        Test.assertEquals(getCount("abracadabra"), 5)
    });
});