How to get key and value of object in javascript?

Question

I have object as var obj = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}] . I want to get key and value this sample

PRODUCT_ID is P01
M01 is 1
M02 is 2
M03 is null

I try with as follow

for (var key in obj) {
  if (obj.hasOwnProperty(key)) {
    console.log(key + " is " + obj[key]);
  }
}

It't not working , it's show wrong with format.

0 is [
1 is {
2 is "
3 is P
4 is R
5 is O
6 is D
...etc

I using javascript to this. If maybe can convert to json and show this .

Seems obj is string, Can you share the output of typeof obj ? — Satpal
– Satpal, Commented Apr 3, 2018 at 12:27
It's array of objects with one object in it. delete "[ ]" and try again. — omer.ersoy
– omer.ersoy, Commented Apr 3, 2018 at 12:30
@BrianCrist I added answer, hope it will work as per your expectation. Thanks — Rohìt Jíndal
– Rohìt Jíndal, Commented Apr 4, 2018 at 5:43

Dimitri · Accepted Answer · 2018-04-03 13:02:23Z

2

My guess is that the object you receive is a string not an actual object or array. This is why with your code, it gives the output.

To convert to an actual JS object use JSON.parse() and it will return an array as expected.

For instance,

const myArray = JSON.parse(obj);
myArray.forEach(x => Object.entries(x).map(([key, value]) => console.log(`${key} is ${value}\n`)))

answered Apr 3, 2018 at 13:02

Dimitri

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Comments

Rohìt Jíndal · Accepted Answer · 2018-04-04 05:42:43Z

1

Observation :

for...in statement iterates over the enumerable properties of an object. Hence, As per the code in OP :

var obj = [{
	"PRODUCT_ID": "P01",
	"M01": 1,
	"M02": 2,
	"M03": null
}];

for (var key in obj) {
  console.log(key); // 0
}

Try this :

var obj = [{
	"PRODUCT_ID": "P01",
	"M01": 1,
	"M02": 2,
	"M03": null
}];

for (var i of obj) {
  for (var j in Object.keys(i)) {
    console.log(Object.keys(i)[j] + " is " + i[Object.keys(i)[j]]);
  }
}

answered Apr 4, 2018 at 5:42

Rohìt Jíndal

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Comments

Scaramouche · Accepted Answer · 2018-04-03 12:29:54Z

1

the problem is you are querying obj, while the actual obj is obj[0]. obj is an array with 1 element. try this

var obj = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}];

for (var key in obj[0]) {
  if (obj[0].hasOwnProperty(key)) {
    console.log(key + " is " + obj[0][key]);
  }
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

answered Apr 3, 2018 at 12:29

Scaramouche

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12 Comments

Alex Over a year ago

That's right. If you could change your obj definition to: obj = {"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}, it'll be more readable

Teemu Over a year ago

It is quite clear, that OP has not an object, please read the question.

Scaramouche Over a year ago

@Teemu, it is quite clear that is exactly what I meant by the actual obj is obj[0]

Teemu Over a year ago

Read the question, take a careful look over the provided output, what you see?

Scaramouche Over a year ago

@BrianCrist, please show the error or some relevant feedback, since it is working in the snippet, I cannot tell what the problem is, do you happen to have more than 1 element in your array obj in your real scenarios?

|

Aniruddha Gohad · Accepted Answer · 2018-04-03 12:49:09Z

1

use Object.keys() method to access the keys in your object and then simply concatenate the key with its value.

this is not the most elegant solution, but it will help you understand.

var obj = '[{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]' //string
obj = JSON.parse(obj);
console.log(Object.keys(obj[0])) //so that you can see what this does

obj.forEach(object => {
   Object.keys(object).forEach(key => {
       $("#values").append($("<p>"+key +" is "+ object[key]+"</p>"));  
   });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="values">
  
</div>

edited Apr 3, 2018 at 12:49

answered Apr 3, 2018 at 12:36

Aniruddha Gohad

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4 Comments

Brian Crist Over a year ago

Sorry , I get with ["0"]

Aniruddha Gohad Over a year ago

I understand that he has an array of object/s and the answer attends to that

Aniruddha Gohad Over a year ago

maybe he edited the question to make it an array? even so, i will attend to that too.

Aniruddha Gohad Over a year ago

@Teemu see snippet for string.

michaelitoh · Accepted Answer · 2018-04-03 12:40:44Z

0

The thing here is that you are treating an array like an object. Change your code for:

for(x=0;x <obj.length;x++){
    // Here you have each object of your array.

     var json = obj[x];
     var arrayOfKeys = Object.keys (json);

    //other code.
 }

edited Apr 3, 2018 at 12:40

answered Apr 3, 2018 at 12:29

michaelitoh

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Comments

Arman Charan · Accepted Answer · 2018-04-03 12:42:02Z

0

See Object.entries(), Array.prototype.map(), and Template Literals for more info.

// Input.
const input = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]

// Output.
input.map(x => Object.entries(x).map(([key, value]) => console.log(`${key} is ${value}\n`)))

edited Apr 3, 2018 at 12:42

answered Apr 3, 2018 at 12:30

Arman Charan

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6 Comments

Teemu Over a year ago

It is quite clear, that OP has not an object, please read the question.

Arman Charan Over a year ago

"I have object" @Teemu

Teemu Over a year ago

That's what they think, look at the output.

Brian Crist Over a year ago

@Teemu i think we should change to json or array . Do you think so ?

Teemu Over a year ago

@BrianCrist At first you've to do JSON.parse to parse your string to an object, then follow some of these answers.

|

CodeNewbie · Accepted Answer · 2018-04-03 12:57:17Z

0

You can use Object.entries() like:

const jsonString = '[{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]'

// parse your json string first
const arr = JSON.parse( jsonString );

// Get the object from the array
const obj = arr[0] || {};

for (const [key, value] of Object.entries(obj)) {
  console.log(key + ' is '+value);
}

edited Apr 3, 2018 at 12:57

answered Apr 3, 2018 at 12:28

CodeNewbie

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1 Comment

CodeNewbie Over a year ago

@BrianCrist Please try to use JSON.parse first to get actual array from the JSON string like show in the demo above.

atiq1589 · Accepted Answer · 2018-04-03 13:06:36Z

0

Your code almost correct. But as you have data array not object you need to loop trough the object to achieve desire output.

Guessing OP has:

var obj = '[{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]';
    for (var key in obj) {
         console.log(key + " is " + obj[key]);
    }

//var obj = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]
var obj = '[{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]';
obj = JSON.parse(obj);
for (var key in obj) {
  for (var k in obj[key]){
     console.log(k + " is " + obj[key][k]);
    }
}

Alternative:

//var obj = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]
var obj = '[{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]';
obj = JSON.parse(obj);
obj.map(e => Object.entries(e).map(([k, v]) => console.log(k, "is", v)))

edited Apr 3, 2018 at 13:06

answered Apr 3, 2018 at 12:52

atiq1589

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8 Comments

Teemu Over a year ago

Your code is almost correct, except it doesn't solve the problem OP is facing. Don't you guys read the questions anymore? Almost all the answers on this post are somewhat useless for OP, including this ...

atiq1589 Over a year ago

@Teemu what OP wants? How to get key and value of object in javascript?

Teemu Over a year ago

Yep, but the gotcha is, that they don't have an object ... Like I said, don't you guys read the questions anymore?

atiq1589 Over a year ago

what do you mean they don't have an object? Op clearly said I have object as var obj = [{"PRODUCT_ID":"P01","M01":1,"M02":2, "M03": null}]

Teemu Over a year ago

Please read the entire question! The output of the provided for ..in loop would totally be different from what OP says they're getting, if they had an object ...

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