Searching recursively for keys with empty values in an array using Javascript

Question

Searching recursively for keys with empty values in an array using Javascript

I've written a function that recursively locates empty values in a nested array.

The function initially produces the correct value, but it seems to reset it to the input value before returning the result.

What could I be overlooking?

Below is my code snippet:

const obj = [
  {
    mainContact: true,
    contactName: "",
    emailId: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="0f6e6d6c4f68626e6663216c6062">[email protected]</a>",
    contactAddress: [
      {
        addressType: "",
        county: "U.K.",
        postCode: "MK7 6BZ",
        houseFlatNumber: 1
      },
      {
        addressType: "def",
        county: "France",
        postCode: "123MKO",
        houseFlatNumber: "223"
      }
    ],
    phoneDetails: [
      {
        notes: "",
        phoneNumber: "1234567899",
        countryCode: "44",
        priority: "1"
      },
      {
        notes: "Lorem ipsum",
        phoneNumber: "1112223331",
        countryCode: "48",
        priority: "2"
      }
    ]
  }
];

function validateObject(obj, isValid) {
  for (var propName in obj) {
    if (typeof obj[propName] === "object") {
      this.validateObject(obj[propName], isValid);
    } else if (
      obj[propName] === null ||
      obj[propName] === undefined ||
      obj[propName] === ""
    ) {
      isValid = false;
      break;
    }
  }
  return isValid;
}

console.log(validateObject(obj), true);
// The expected output should be false, yet it returns true even though it first encountered and set isValid to false

Any assistance would be highly appreciated.

Thank you.

javascript for-loop recursion nested-loops

Answer 1

Answer №1

When it comes to recursion, one important thing to remember is that you must always ensure to return the value from your recursive call. This involves calling the function from within itself and then handling the return value appropriately.

Upon analyzing your function, I have made some adjustments by introducing a basic base case to verify if the input value is null, undefined, or an empty string.

function isValidObject(obj) {
  // Base case
  if (obj[propName] === null || obj[propName] === undefined || obj[propName] === '') {
    return false;
  }
  
  // Recursively check each item in object
  if (typeof obj === "object") {
    for (var propName in obj) {
      if (!isValidObject(obj[propName]) {
        return false;
      }
    }
  }
  return true;
}

It's worth noting that this modification eliminates the need for a boolean parameter in your function by simply returning false when the first invalid condition is encountered.

Answer 2

When it comes to recursion, one important thing to remember is that you must always ensure to return the value from your recursive call. This involves calling the function from within itself and then handling the return value appropriately.

Upon analyzing your function, I have made some adjustments by introducing a basic base case to verify if the input value is null, undefined, or an empty string.

function isValidObject(obj) {
  // Base case
  if (obj[propName] === null || obj[propName] === undefined || obj[propName] === '') {
    return false;
  }
  
  // Recursively check each item in object
  if (typeof obj === "object") {
    for (var propName in obj) {
      if (!isValidObject(obj[propName]) {
        return false;
      }
    }
  }
  return true;
}

It's worth noting that this modification eliminates the need for a boolean parameter in your function by simply returning false when the first invalid condition is encountered.

Answer 3

Answer №2

The main issue at hand is the failure to return the value of the recursive call. This means that you are essentially creating an inline recursive loop and then returning the result from the higher callable.

Furthermore, due to isOk being a primitive boolean, it follows pass by value behavior rather than pass by reference. Consequently, any changes made to isOk within a nested function do not affect the variable in the parent context.

It's important to note that this rule does not extend to obj[propName], which operates on pass by reference principles. As a result, any alterations made to the data inside the function will be reflected outside of its scope.

function validateObject(obj) {
  for (var propName in obj) {
    if( typeof obj[propName] === "object" ) {
      if( validateObject(obj[propName]) === false ) {
        // The updated status will be passed up through the call stack
        return false;
     }
   } 
   else if (
     obj[propName] === null      || 
     obj[propName] === undefined || 
     obj[propName] === ''
   ) {
     return false;  // no variable required here
   }
 }
 return true;  // logic dictates - if nothing is false, it must be true
}

Answer 4

The main issue at hand is the failure to return the value of the recursive call. This means that you are essentially creating an inline recursive loop and then returning the result from the higher callable.

Furthermore, due to isOk being a primitive boolean, it follows pass by value behavior rather than pass by reference. Consequently, any changes made to isOk within a nested function do not affect the variable in the parent context.

It's important to note that this rule does not extend to obj[propName], which operates on pass by reference principles. As a result, any alterations made to the data inside the function will be reflected outside of its scope.

function validateObject(obj) {
  for (var propName in obj) {
    if( typeof obj[propName] === "object" ) {
      if( validateObject(obj[propName]) === false ) {
        // The updated status will be passed up through the call stack
        return false;
     }
   } 
   else if (
     obj[propName] === null      || 
     obj[propName] === undefined || 
     obj[propName] === ''
   ) {
     return false;  // no variable required here
   }
 }
 return true;  // logic dictates - if nothing is false, it must be true
}

Answer 5

Answer №3

A different approach involves creating a versatile function that recursively checks the validity of object properties based on a given predicate.

It's not complex, in my opinion, and is often easier than directly writing a specialized function. Applying it to a specific scenario is also straightforward.

Here's an example:

const checkValidity = (predicate) => (object) =>
  Object.values(object).every(
    value => (value && typeof value === 'object') ? checkValidity(predicate)(value) : predicate(value)
  )

const noEmptyValues = checkValidity(val => val !== '' && val != null)

const objectExample = [{mainContact: true, contactName: "", emailId: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="bedfdcddfed9d3dfd7d290ddd1d3">[email protected]</a>", contactAddress: [{addressType: "", county: "U.K.", postCode: "MK7 6BZ", houseFlatNumber: 1}, {addressType: "def", county: "France", postCode: "123MKO", houseFlatNumber: "223"}], phoneDetails: [{notes: "", phoneNumber: "1234567899", countryCode: "44", priority: "1"}, {notes: "Lorem ipsum", phoneNumber: "1112223331", countryCode: "48", priority: "2"}]}]

console.log(noEmptyValues(objectExample))

Answer 6

A different approach involves creating a versatile function that recursively checks the validity of object properties based on a given predicate.

It's not complex, in my opinion, and is often easier than directly writing a specialized function. Applying it to a specific scenario is also straightforward.

Here's an example:

const checkValidity = (predicate) => (object) =>
  Object.values(object).every(
    value => (value && typeof value === 'object') ? checkValidity(predicate)(value) : predicate(value)
  )

const noEmptyValues = checkValidity(val => val !== '' && val != null)

const objectExample = [{mainContact: true, contactName: "", emailId: "<a href="/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="bedfdcddfed9d3dfd7d290ddd1d3">[email protected]</a>", contactAddress: [{addressType: "", county: "U.K.", postCode: "MK7 6BZ", houseFlatNumber: 1}, {addressType: "def", county: "France", postCode: "123MKO", houseFlatNumber: "223"}], phoneDetails: [{notes: "", phoneNumber: "1234567899", countryCode: "44", priority: "1"}, {notes: "Lorem ipsum", phoneNumber: "1112223331", countryCode: "48", priority: "2"}]}]

console.log(noEmptyValues(objectExample))

Answer 7

Answer №4

Big shoutout to James McGuigan for helping me refine this piece of code:


isValidObject(obj) {

    for (var propName in obj) {
        if( typeof obj[propName] === "object" ) {
            if( this.isValidObject(obj[propName]) === false || 
                obj[propName] === null || 
                obj[propName].length === 0 ) 
            {
                return false;
            }
        } 
        else if (
                obj[propName] === null      || 
                obj[propName] === undefined || 
                obj[propName] === '' 
                ) {
                    return false;  
                }
    }
    return true;  

}

Answer 8

Big shoutout to James McGuigan for helping me refine this piece of code:


isValidObject(obj) {

    for (var propName in obj) {
        if( typeof obj[propName] === "object" ) {
            if( this.isValidObject(obj[propName]) === false || 
                obj[propName] === null || 
                obj[propName].length === 0 ) 
            {
                return false;
            }
        } 
        else if (
                obj[propName] === null      || 
                obj[propName] === undefined || 
                obj[propName] === '' 
                ) {
                    return false;  
                }
    }
    return true;  

}

Searching recursively for keys with empty values in an array using Javascript

Answer №1

Answer №2

Answer №3

Answer №4

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