Question

我是一名React开发人员，在Vanilla JS中需要完成一些任务，我不知道我在这里做错了什么。

这是一个简单的选择

 <select id="js-year-selected" onchange="getYear()" class="js-year-input">
                <option value="2020">2020</option>
                <option value="2019" >2019</option>
                <option value="2018">2018</option>
                <option value="2017">2017</option>
                <option value="2016" >2016</option>
                <option value="2015">2015</option>
                <option value="2014">2014</option>
</select>

这是onchange功能：-

function getYear() {
  var getYear = document.getElementById("js-year-selected");
  var strUser = getYear.options[getYear.selectedIndex].value;
  var getJSON = document.getElementById("json-input").innerHTML;

  data = JSON.parse(getJSON);
  var year = strUser;
  console.log(year);

  let filterDataUtil = data.filter(function(dataItem) {
    return dataItem.birthday.split("/")[2].localeCompare(strUser) !== -1;
  });
  console.log(filterDataUtil)
}

无论我说的是哪一年，它只返回2020年的值并将其附加新值。

示例JSON

<textarea class="app__txt js-json" id="json-input" placeholder="Paste the json here.">[
    {
      "name": "Tyrion Lannister",
      "birthday": "12/02/2020"
    }, {
      "name": "Cersei Lannister",
      "birthday": "11/30/1975"
    }, {
      "name": "Daenerys Targaryen",
      "birthday": "11/24/1991"
    }, {
      "name": "Arya Stark",
      "birthday": "11/25/2020"
    }, {
      "name": "Jon Snow",
      "birthday": "12/03/1989"
    }, {
      "name": "Sansa Stark",
      "birthday": "08/15/1992"
    }, {
      "name": "Jorah Mormont",
      "birthday": "12/16/1968"
    }
]</textarea>

Answer 1

您使用的--use derived table and case statment: --you can give your date in case statement and give proper aliases in order to avoid errors during execution --this query will give you all records from info table and you can also get info for availability and not available also SELECT * FROM ( SELECT Availability.availability_id, Availability.availability_date, Availability.availability_start, Availability.availability_end, Info.info_id, Info.info_firstname, Info.info_surname, Job.job_name ,case when Availability.availability_date = '2019-09-20' then 'AVAILABLE' ELSE 'NOT AVAILABLE' END STATUS FROM Info left join Availability ON Availability.availability_info_id = Info.info_id LEFT JOIN Job ON Job.job_id = Info.info_job_id WHERE Availability.availability_date = '2019-09-20'; --//today ) T WHERE STATUS='NOT AVAILABLE' --THIS WILL GIVE YOU INFO WHICH HAS NO '2019-09-20' IN availability_date COLUMN错误-当字符串相等时，它返回localeCompare，或者根据两个字符串的比较方式，返回负/正数。

在这种情况下，您只有两个包含年份的字符串，因此只需使用0进行比较。

Answer 2

需要简单的比较

dataItem.birthday.split("/")[2] === strUser;

function getYear() {
  var getYear = document.getElementById("js-year-selected");
  var strUser = getYear.options[getYear.selectedIndex].value;
  var getJSON = document.getElementById("json-input").innerHTML;

  data = JSON.parse(getJSON);
  var year = strUser;

  let filterDataUtil = data.filter(function(dataItem) {
    return dataItem.birthday.split("/")[2] === strUser;
  });
}

 <select id="js-year-selected" onchange="getYear()" class="js-year-input">
                <option value="2020">2020</option>
                <option value="2019" >2019</option>
                <option value="2018">2018</option>
                <option value="2017">2017</option>
                <option value="2016" >2016</option>
                <option value="2015">2015</option>
                <option value="2014">2014</option>
</select>

<textarea class="app__txt js-json" id="json-input" placeholder="Paste the json here.">[
    {
      "name": "Tyrion Lannister",
      "birthday": "12/02/2020"
    }, {
      "name": "Cersei Lannister",
      "birthday": "11/30/1975"
    }, {
      "name": "Daenerys Targaryen",
      "birthday": "11/24/1991"
    }, {
      "name": "Arya Stark",
      "birthday": "11/25/2020"
    }, {
      "name": "Jon Snow",
      "birthday": "12/03/1989"
    }, {
      "name": "Sansa Stark",
      "birthday": "08/15/1992"
    }, {
      "name": "Jorah Mormont",
      "birthday": "12/16/1968"
    }
]</textarea>

Answer 3

您需要比较两个字符串：

function getYear() {
  var getYear = document.getElementById("js-year-selected");
  var strUser = getYear.options[getYear.selectedIndex].value;
  var getJSON = document.getElementById("json-input").innerHTML;

  data = JSON.parse(getJSON);
  var year = strUser;
  console.log(year);

  let filterDataUtil = data.filter(function(dataItem) {
    if(dataItem.birthday.split("/")[2] === strUser){
      return dataItem;
    };
  });
  console.log(filterDataUtil)
}

Answer 4

如果要获取Array，则可以按照以下说明进行操作

let filterDataUtil = data.filter(function(dataItem) {
    return dataItem.birthday.split("/")[2] == strUser;
  });
console.log(filterDataUtil);

如果只想获取对象，则可以按照以下说明进行操作

let filterDataUtil = data.find(dataItem => dataItem.birthday.split("/")[2] == strUser);
console.log(filterDataUtil);

为什么每次都重复相同的数组？

4 个答案: