Some elements in the Javascript variable list obj.names are null while others maintain values

Question

Some elements in the Javascript variable list obj.names are null while others maintain values

I'm currently working on compiling a list from an array, but I've encountered an issue where some of the fields are null, causing the code to break and return:

obj.names is null

Below is the snippet of code that's causing the problem:

My Code

var data = {
  "people": [{
      "id": "32",
      "description": "some description",
      "archived": "",
      "new": 0,
      "names": [{
        "name": "name 1",
        "translations": null
      }, {
        "name": "name 2",
        "translations": null
      }],
    }, {
      "id": "56",
      "description": "some description",
      "archived": "",
      "new": 0,
      "names": [{
        "name": "name 3",
        "translations": null
      }, {
        "name": "name 4",
        "translations": null
      }],
    }, {
      "id": "99",
      "description": "some description",
      "archived": "",
      "new": 0,
      "names": null,
    },

  ]
};

var mainData = [data];
var namesList = [];

for (var i = 0; i < mainData[0].people.length; i++) {

  var obj = mainData[0].people[i];
  
  if(obj.names) {
    var nme = obj.names.name;
    namesList.push(nme);
  }
}

console.log(namesList); //This should have the list of names

<div id="container"></div>

JSFiddle Link

How can this issue be resolved?

javascript arrays object

Answer 1

Answer №1

labels is a list of elements, you must extract the label attribute from each element in the labels list.

Revise these statements

var lbl = obj.labels.label;
listOfLabels.push(lbl);

with

if( obj.labels )
{
   var lbl = obj.labels.map( function(item){
    return item.label; 
   });
   listOfLabels = listOfLabels.concat(lbl);
}

The map function is utilized to loop through the list and retrieve the label attribute of each element.

Answer 2

labels is a list of elements, you must extract the label attribute from each element in the labels list.

Revise these statements

var lbl = obj.labels.label;
listOfLabels.push(lbl);

with

if( obj.labels )
{
   var lbl = obj.labels.map( function(item){
    return item.label; 
   });
   listOfLabels = listOfLabels.concat(lbl);
}

The map function is utilized to loop through the list and retrieve the label attribute of each element.

Answer 3

Answer №2

I find array methods like map, reduce, and forEach to be very useful.

When using these methods, the resulting code might look something like this:

// In this example, we are looping over the people array but creating a new array with all the names from the names array using reduce.
var namesList = data.people.reduce(function( resultArray, person ) {
    // Concatenate names from the names array to our result
    return resultArray.concat(
        // Check if the names array exists before mapping through it
        person.names && person.names.map(function( nameObj ) {
            return nameObj.name;
        }) || []
    );
}, []);

Answer 4

I find array methods like map, reduce, and forEach to be very useful.

When using these methods, the resulting code might look something like this:

// In this example, we are looping over the people array but creating a new array with all the names from the names array using reduce.
var namesList = data.people.reduce(function( resultArray, person ) {
    // Concatenate names from the names array to our result
    return resultArray.concat(
        // Check if the names array exists before mapping through it
        person.names && person.names.map(function( nameObj ) {
            return nameObj.name;
        }) || []
    );
}, []);

Some elements in the Javascript variable list obj.names are null while others maintain values

Answer №1

Answer №2

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