javascript - validate nested key inside an object [duplicate]

Question

I have the following JavaScript object.

let obj = {
  "type": "user",
  "personalDetails": {
    "firstName": "Steven",
    "address": {
      "streetName": "abcd",
      "zipCode": "012345"
    }
  },
  "employeeDetails": {
    "designation": {
      "id": "1234",
      "manage": "Mark",
    }
  }
}

How can I create a dynamic function which will take this JS object obj as a first argument, one parent node as the second argument and a child node as the third argument.

if the third argument is present as a child node inside the second argument, the function should return true. For example.

const childNodeExist = (obj, personalDetails, firstName) => {
    //.. since firstName exists in personalDetails should return true
}

const childNodeExist = (obj, employeeDetails, designation) => {
    //.. since designation exists in employeeDetails should return true
}
const childNodeExist = (obj, employeeDetails, salary) => {
    //.. since salary exists in employeeDetails should return false
}

Mamun · Accepted Answer · 2021-08-23 06:45:36Z

1

You can try using Object.prototype.hasOwnProperty():

The hasOwnProperty() method returns a boolean indicating whether the object has the specified property as its own property (as opposed to inheriting it).

let obj = {
  "type": "user",
  "personalDetails": {
    "firstName": "Steven",
    "address": {
      "streetName": "abcd",
      "zipCode": "012345"
    }
  },
  "employeeDetails": {
    "designation": {
      "id": "1234",
      "manage": "Mark",
    }
  }
}

const childNodeExist = (obj, prop, childProp) => {
    return obj[prop]?.hasOwnProperty(childProp) ?? false; 
}
console.log(childNodeExist(obj, 'personalDetails', 'firstName'));

console.log(childNodeExist(obj, 'employeeDetails', 'designation'));

console.log(childNodeExist(obj, 'employeeDetails', 'salary'));

Update: Alternative way to support in all the browsers:

let obj = {
  "type": "user",
  "personalDetails": {
    "firstName": "Steven",
    "address": {
      "streetName": "abcd",
      "zipCode": "012345"
    }
  },
  "employeeDetails": {
    "designation": {
      "id": "1234",
      "manage": "Mark",
    }
  }
}

const childNodeExist = (obj, prop, childProp) => {
    return obj.hasOwnProperty(prop)? obj[prop].hasOwnProperty(childProp) : false; 
}
console.log(childNodeExist(obj, 'personalDetails', 'firstName'));

console.log(childNodeExist(obj, 'employeeDetails', 'designation'));

console.log(childNodeExist(obj, 'employeeDetails', 'salary'));

edited Aug 23, 2021 at 6:45

answered Aug 23, 2021 at 6:24

Mamun

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3 Comments

DecPK Over a year ago

Another way is return Object.keys(obj[prop]).includes(childProp);

user2281858 Over a year ago

@Mamun, optional chaining ? might not work in all the browsers, right? Alternate way?

Mamun Over a year ago

@user2281858, added second solution without using the ?., please check:)

ahsan · Accepted Answer · 2021-08-23 06:26:29Z

1

Is this what you require?

const childNodeExist = (obj, parentNode, childNode) => {
    return (obj[parentNode][childNode] ? true : false);
}

let obj = {
  "type": "user",
  "personalDetails": {
    "firstName": "Steven",
    "address": {
      "streetName": "abcd",
      "zipCode": "012345"
    }
  },
  "employeeDetails": {
    "designation": {
      "id": "1234",
      "manage": "Mark",
    }
  }
}

console.log(childNodeExist(obj, "personalDetails", "firstName"));
console.log(childNodeExist(obj, "employeeDetails", "designation"));
console.log(childNodeExist(obj, "employeeDetails", "salary"));

answered Aug 23, 2021 at 6:26

ahsan

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Comments

Erfan · Accepted Answer · 2021-08-23 06:27:38Z

1

This would do the trick:

  const childNodeExist = (obj, parentNode, childNode) => Boolean(obj[parentNode][childNode])

answered Aug 23, 2021 at 6:27

Erfan

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