JS Cannot read property “length” of undefined [closed]

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Closed 2 years ago.

I'm trying to create an object using a given string where each word has a property stating its length.

var strings = {};

function findLongestWord(str) {
  var splitStr = str.split(" ");
    for (var i = 0; i <= str.length; i++){
     strings[splitStr[i]] = splitStr[i].length;
  }

  return strings;
}

findLongestWord("The quick brown fox jumped over the lazy dog");

I end up getting:

"TypeError": Cannot read property "length" of undefined.

If I were to replace splitStr[i].length with splitStr[0].length, the code runs properly, but of course giving me the same number for each word in the object.

Any help is appreciated, thanks.

回答1:

you are looping over wrong array. you should use i < splitStr.length.

  var strings = {};    
  function findLongestWord(str) {
  var splitStr = str.split(" ");
    for (var i = 0; i < splitStr.length; i++){
     strings[splitStr[i]] = splitStr[i].length;
  }

  return strings;
}

来源：https://stackoverflow.com/questions/44916065/js-cannot-read-property-length-of-undefined