Convert string true/false to boolean in JSON response

Question

I have a scenario where many fields in JSON response that are coming as string ("true"/"false").

Now I need to replace all of the values from string to Boolean in one shot via Javascript.

Sample:

{
    field1: "true",
    field2: "false"
}

Expected:

{
    field1: true,
    field2: false
}

This is a sample. My JSON response is very huge with many objects and arrays.

Are you in control of generating your JSON response? If so, just fix your response. JSON supports booleans. Why not use them? Anyway, you can convert `"false"` to `false` and `"true"` to `true` with `JSON.parse`. [`Object`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object#Methods_of_the_Object_constructor) and [`Array`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array#Methods) methods may help here as well. — Sebastian Simon, Jul 15 '18 at 05:45
Possible duplicate of [How can I convert a string to boolean in JavaScript?](https://stackoverflow.com/questions/263965/how-can-i-convert-a-string-to-boolean-in-javascript) — Alexander, Jul 15 '18 at 05:45
@Alexander No, this isn't duplicate. There is converting a single variable - here is converting a whole object. — Chayim Friedman, Jul 15 '18 at 06:11
There are no absolute same questions on the site, but the above mentioned topic aswer how to cast object fields to boolean ,@חייםפרידמן — Alexander, Jul 15 '18 at 06:21
@Alexander While I agree with you that there are no absolute same questions, I do agree that while that link may help, this question is sufficiently different to not warrant a close vote. — Blue, Jul 15 '18 at 06:25
@חייםפרידמן What I mean is that `JSON.parse("true") === true` and `JSON.parse("false") === false`. — Sebastian Simon, Jul 15 '18 at 14:29

score 11 · Answer 1 · answered Jul 15 '18 at 06:15

11

The JSON.parse reviver parameter can be used to exclude or modify values:

var j = '{"field1":"true","field2":"false"}';

var o = JSON.parse(j, (k, v) => v === "true" ? true : v === "false" ? false : v);

console.log(o);

answered Jul 15 '18 at 06:15

Slai

22,144
5
45
53

I didn't know about the reviver function. This is pretty cool, and an alternative (And works recursively!). – Blue Jul 15 '18 at 06:35

Blue · Answer 2 · 2018-07-15T06:24:01.360

Here's a nice recursive convertBools function:

function convertBools(obj) {
  const newObj = {};
  
  if (typeof obj !== 'object') {
    return obj;
  }
  
  for (const prop in obj) {
    if (!obj.hasOwnProperty(prop)) {
      continue;
    }
    if (Array.isArray(obj[prop])) {
      newObj[prop] = obj[prop].map(val => convertBools(val));
    } else if (obj[prop] === "true") {
      newObj[prop] = true;
    } else if (obj[prop] === "false") {
      newObj[prop] = false;
    } else {
      newObj[prop] = convertBools(obj[prop]);
    }
  }
  
  return newObj;
}

// Some examples below:
const obj1 = {
  field1: "true",
  field2: "false"
};

const obj2 = {
  field1: "true",
  field2: "asdf",
  field3: "false",
  field4: {
    field4a: "true",
    field4b: "asdf",
    field4c: ["a", {"array1": "true"}, "c"],
  }
}

const ret1 = convertBools(obj1);

console.log(ret1);

const ret2 = convertBools(obj2);

console.log(ret2);

Syed Arif Iqbal · Answer 3 · 2018-07-15T06:23:31.350

0

you can try something like this as well.

let obj = {
    field1: "true",
    field2: "false",
    field3: "SomeOtherValueThanBoolean"
};

for (let prop in obj) {
    if (obj.hasOwnProperty(prop)) {
        obj[prop] = (obj[prop] == 'true' || obj[prop] == 'false')? obj[prop] === 'true': obj[prop] ;
    }
}

console.log(obj);

edited Jul 15 '18 at 06:23

answered Jul 15 '18 at 06:18

Syed Arif Iqbal

1,830
12
16

As stated in his original question "My JSON response is very huge with many objects and arrays.". This answer does not satisfy that. – Blue Jul 15 '18 at 06:27

score 0 · Answer 4 · answered Apr 23 '20 at 11:51

My version, does not modify source object, returns new object with parsed booleans:

const object = {
  "test": "true",
  "test1": false,
  "test2": "false",
  "test3": 5,
}

console.log(parseBooleansInObj(object));


function parseBooleansInObj(object) {
  const newObject = { ...object };
  Object.keys(newObject)
    .forEach((objKey) => {
      let value = newObject[objKey];
      value = (value === 'true' ? true : value === 'false' ? false : value);
      newObject[objKey] = value;
    });
  return newObject;
}

Convert string true/false to boolean in JSON response

4 Answers4