how to add to query parameter if value is not null in javascript

Question

I am add query string like this:

reportQuery: function (params) {
    var that = this;
    var queryData = {
      "patient_id": params.exampleNo,
      "hospital_name": params.hospitalName,
      "item_name": params.checkItem,
      "report_date": params.reportDate
    };
    API.executeGet(queryData, function (res) {
      if (res.data.Data && res.data.Data.length > 0) {
        that.setData({
          reportList: res.data.Data,
          containsData: true
        });
      }
    }, '/api/Analysis/Search', 'post');
  }

but sometimes the params.exampleNo or params.checkItem is null or undefined. What is the clean write way to add the value to query if it is not null? For example, if params.checkItem is null, my query should look like this:

       var queryData = {
          "patient_id": params.exampleNo,
          "hospital_name": params.hospitalName,
          "report_date": params.reportDate
        };

when It is null, just ignore it. If write like this:

if(value){
   var queryData ={
   }
}

It is ugly.

Object.keys(params).reduce((a,c) => params[c] ? {...a, [c]: params[c] } : a, {}) — user13198697
– user13198697, Commented Apr 12, 2020 at 8:46
I've updated my answer, I think you need some sort of map to link the params keys with the queryData keys as they are different. Please check the second snippet below and let me know if it solved your question. — Luís Ramalho
– Luís Ramalho, Commented Apr 12, 2020 at 9:07

Luís Ramalho · Accepted Answer · 2020-04-12 09:19:42Z

1

You could just have a guard clause at the top of the function that will return from the function if params === null, like:

function(params) {
  if (params === null) return;

  var that = this;
  var queryData = {
    "patient_id": params.exampleNo,
    "hospital_name": params.hospitalName,
    "item_name": params.checkItem,
    "report_date": params.reportDate
  };

  API.executeGet(queryData, function(res) {
    if (res.data.Data && res.data.Data.length > 0) {
      that.setData({
        reportList: res.data.Data,
        containsData: true
      });
    }
  }, '/api/Analysis/Search', 'post');
}

If you want to check if some value in params is falsy (null, undefined, NaN, empty string (""), false or 0), then you can do something like:

params = {
  exampleNo: 42,
  hospitalName: 'Gotham General Hospital',
  checkItem: null,
  reportDate: "01/01/1970",
};

let map = {
  exampleNo: "patient_id",
  hospitalName: "hospital_name",
  checkItem: "item_name",
  reportDate: "report_date",
};

let query = Object.entries(params).reduce((p, [k, v]) => {
  if (v) p[map[k]] = v;
  return p;
}, {});

console.log(query);

// {
//   "patient_id": 42,
//   "hospital_name": "Gotham General Hospital",
//   "report_date": "01/01/1970"
// }

edited Apr 12, 2020 at 9:19

answered Apr 12, 2020 at 8:39

Luís Ramalho

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2 Comments

Dolphin Over a year ago

if the params contained value is null,how to handle property.

Luís Ramalho Over a year ago

So you want to return in case any property of params is null or undefined? In that case you'll have to loop through them and check if any is null/undefined and return. The code above only works for the null case, if you want for undefined as well you can do if (!params) return;

aami · Accepted Answer · 2020-04-12 09:20:03Z

1

let params = {
  exampleNo: null,
  hospitalName: undefined,
  checkItem: true,
  reportDate: "42",
};
let newObj = {};
Object.keys(params).forEach((item) =>{
    if(params[item]){ newObj[item] = params[item]}
} );
console.log('get newbj', newObj);

You can pass newObj as your queryData.

answered Apr 12, 2020 at 9:20

aami

111 bronze badge

1 Comment

Luís Ramalho Over a year ago

The queryData keys are different from the params keys.

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