Convert an string to object with duplicate keys to an array

Question

I have a string that needs to be converted to an object. But the string has the duplicated items. Since JSON Objects cannot contain 2 items with the same key. The second item is overwriting the first item. How to merge the duplicate items and push to an array?

var string = "test-1=owner&test-1=driver&test-2=Yes&test-3=2&test-4=sun&test-4=moon&test-5=not-agree&test-6=dogs&test-6=testing+js+object&test-7=Testing+js+function&test-7=Testing+js+array"

var stringMod = string.split("&");


var stringObj = {};

stringMod.forEach(function(json) {
  var jsonSplit = json.split("=");

  stringObj[jsonSplit[0]] = [jsonSplit[1]];
});

console.log(stringObj,'stringObj');

Desired output:

{
  "test-1": ["owner","driver"],
  "test-2": ["Yes"],
  "test-3": ["2"],
  "test-4": ["sun","moon"],
  "test-5": ["not-agree"],
  "test-6": ["dogs","testing+js+object"],
  "test-7": ["Testing+js+function","Testing+js+array"]
}

Here is the link to working fiddle: https://jsfiddle.net/sjoh9rqp/

Can you help me how to accomplish this ?

Using [...(stringObj?.[jsonSplit[0]] || []), jsonSplit[1]]; might work. (It's not pretty though) — evolutionxbox
– evolutionxbox, Commented Jul 21, 2021 at 0:09

Musa · Accepted Answer · 2021-07-21 00:16:50Z

4

You can use a URLSearchParams to accomplish this, since it treats the string as url parameters it does do decoding though.

var string = "test-1=owner&test-1=driver&test-2=Yes&test-3=2&test-4=sun&test-4=moon&test-5=not-agree&test-6=dogs&test-6=testing+js+object&test-7=Testing+js+function&test-7=Testing+js+array"

var data = new URLSearchParams(string);
var obj = {};
for (let x of data.keys()){
  obj[x] = data.getAll(x);
}
console.log(obj);

answered Jul 21, 2021 at 0:16

Musa

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Comments

charlietfl · Accepted Answer · 2021-07-21 00:19:33Z

3

Using URLSearchParams to parse the query string helps simplify this

var string = "test-1=owner&test-1=driver&test-2=Yes&test-3=2&test-4=sun&test-4=moon&test-5=not-agree&test-6=dogs&test-6=testing+js+object&test-7=Testing+js+function&test-7=Testing+js+array"

const params = new URLSearchParams(string),
      res = {};


params.forEach((v,k)=> { 
  res[k] = res[k] || []
  res[k].push(v);  
})

console.log(res)

answered Jul 21, 2021 at 0:19

charlietfl

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Comments

Kinglish · Accepted Answer · 2021-07-21 00:21:54Z

1

For variety, here's the answer solved with reduce(), though I have to admit URLSearchParams is more elegant

var string = "test-1=owner&test-1=driver&test-2=Yes&test-3=2&test-4=sun&test-4=moon&test-5=not-agree&test-6=dogs&test-6=testing+js+object&test-7=Testing+js+function&test-7=Testing+js+array"

let obj = string.split('&').reduce((b,a) => {
  let t = a.split('=');
  if (b.hasOwnProperty(t[0])) b[t[0]].push(t[1]);
  else  b[t[0]] =[t[1]];
  return b;
},{});
console.log(obj)

edited Jul 21, 2021 at 0:21

answered Jul 21, 2021 at 0:14

Kinglish

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