Is there a way to verify if a value is undefined before including it as an object field?

Question

Is there a way to verify if a value is undefined before including it as an object field?

I'm currently working on an Angular project and I have a query regarding TypeScript. It's about correctly handling the scenario where a field should not be included in an object if its value is undefined.

In my code, I am initializing an object like this:

let aestheticEvaluation: AestheticEvaluation = {
    "altezza": aestheticEvaluationInfo.get('altezza').value,
    "peso": aestheticEvaluationInfo.get('peso').value,
    
    // other fields
    
    "notes": aestheticEvaluationInfo.get('notes').value,
};

The issue arises when some fields may have an undefined value. In such cases, these fields should not be added to the aestheticEvaluation object.

For instance, if the value of aestheticEvaluationInfo.get('altezza').value is undefined, the "altezza" field should not be included in the object.

I'm aware that I can use conditional statements to check for null values before adding each field to the object, but this would make the code more repetitive. Is there a way to handle this directly within the object initialization?

javascript angular typescript javascript-objects

Answer 1

Answer №1

I have a couple of solutions in mind, so you can choose the one that best fits your needs.

Instead of having undefined values, you can set default values such as an empty string '' or zero for numbers.

const object = {
    key: anotherObject?.attribute || ''
};

Another approach is to set the object values first and then clean up the object by removing any undefined values:

const object = { key: value };

Object.keys(object).forEach(key => {
    if (!object[key]) delete object[key];
});

If there's anything I'm not understanding correctly, please let me know.

Answer 2

I have a couple of solutions in mind, so you can choose the one that best fits your needs.

Instead of having undefined values, you can set default values such as an empty string '' or zero for numbers.

const object = {
    key: anotherObject?.attribute || ''
};

Another approach is to set the object values first and then clean up the object by removing any undefined values:

const object = { key: value };

Object.keys(object).forEach(key => {
    if (!object[key]) delete object[key];
});

If there's anything I'm not understanding correctly, please let me know.

Answer 3

Answer №2

  const userEvaluation: UserEvaluation = {
   "height": userEvaluationInfo.get('height').value,
   "weight": userEvaluationInfo.get('weight').value,
   .... and so forth
  }


  for(const key in userEvaluation)
  { 
   if(!userEvaluation[key]) 
    delete userEvaluation[key]
   }

    !userEvaluation[key] = This will remove all falsy values like 
    null, undefined, 0, ''.
    If you only want to filter out undefined value, you can do 
   for(const key in userEvaluation)
    { 
     if(typeof userEvaluation[key] === "undefined") 
      delete userEvaluation[key]
    }

Answer 4

  const userEvaluation: UserEvaluation = {
   "height": userEvaluationInfo.get('height').value,
   "weight": userEvaluationInfo.get('weight').value,
   .... and so forth
  }


  for(const key in userEvaluation)
  { 
   if(!userEvaluation[key]) 
    delete userEvaluation[key]
   }

    !userEvaluation[key] = This will remove all falsy values like 
    null, undefined, 0, ''.
    If you only want to filter out undefined value, you can do 
   for(const key in userEvaluation)
    { 
     if(typeof userEvaluation[key] === "undefined") 
      delete userEvaluation[key]
    }

Answer 5

Answer №3

Looking at a unique approach to handling criteria declarations, this method simplifies the process by allowing each criteria to be declared only once and making it easy to interchange methods for obtaining values with just one line of code.

const beautyCriteria: string[] = [
  "height",
  "weight",
  "skinType",
  "photoaging",
  "blackheads",
  "varicoseVeins",
  "wrinkleLines",
  "nasolabialFoldsIntensity",
  "neckAgingDegree",
  "darkCircles",
  "eyeBags",
  "lowerThirdHypotonia",
  "cellulite",
  "hypertrophicKeloidScars",
  "Wood'sLight",
  "additionalNotes",
]

let beautyEvaluation: BeautyEvaluation = {}
beautyCriteria.forEach((criteria) => {
  const value = beautyInfo.get(criteria).value
  if (value){
    beautyEvaluation[criteria] = value
  }
})
//beautyEvaluation object is now populated with specified criteria/values
console.log(beautyEvaluation)

Answer 6

Looking at a unique approach to handling criteria declarations, this method simplifies the process by allowing each criteria to be declared only once and making it easy to interchange methods for obtaining values with just one line of code.

const beautyCriteria: string[] = [
  "height",
  "weight",
  "skinType",
  "photoaging",
  "blackheads",
  "varicoseVeins",
  "wrinkleLines",
  "nasolabialFoldsIntensity",
  "neckAgingDegree",
  "darkCircles",
  "eyeBags",
  "lowerThirdHypotonia",
  "cellulite",
  "hypertrophicKeloidScars",
  "Wood'sLight",
  "additionalNotes",
]

let beautyEvaluation: BeautyEvaluation = {}
beautyCriteria.forEach((criteria) => {
  const value = beautyInfo.get(criteria).value
  if (value){
    beautyEvaluation[criteria] = value
  }
})
//beautyEvaluation object is now populated with specified criteria/values
console.log(beautyEvaluation)

Answer 7

Answer №4

To ensure each value in the object is checked before creation, a function can be implemented as shown below.

// defining an object `aestheticEvaluationInfo` using the Map data structure
let aestheticEvaluationInfo = new Map();
aestheticEvaluationInfo.set('height', { value: { name: 'height'}});
aestheticEvaluationInfo.set('weight', { value: { name: 'weight'}});
.
.
.
// other fields omitted for brevity
aestheticEvaluationInfo.set('notes', undefined);

function createObjectWithValidValues(data) {
  let obj = {};
  for (const [key, value] of data.entries()) {
    if (value) obj[key] = value.value.name;
  }
  return obj;
}

console.log(createObjectWithValidValues(aestheticEvaluationInfo));

Answer 8

To ensure each value in the object is checked before creation, a function can be implemented as shown below.

// defining an object `aestheticEvaluationInfo` using the Map data structure
let aestheticEvaluationInfo = new Map();
aestheticEvaluationInfo.set('height', { value: { name: 'height'}});
aestheticEvaluationInfo.set('weight', { value: { name: 'weight'}});
.
.
.
// other fields omitted for brevity
aestheticEvaluationInfo.set('notes', undefined);

function createObjectWithValidValues(data) {
  let obj = {};
  for (const [key, value] of data.entries()) {
    if (value) obj[key] = value.value.name;
  }
  return obj;
}

console.log(createObjectWithValidValues(aestheticEvaluationInfo));

Is there a way to verify if a value is undefined before including it as an object field?

Answer №1

Answer №2

Answer №3

Answer №4

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