Asking about if conditional in array javascript

Question

I have array structure like this:

array[1].name = "parameter-name";
array[1].value = null;
array[2].name = null;
array[2].value = "parameter-value2";

i want to change null to "".

This is how I display in ajax:

for (var i in array) {

    if(array[i].name == null) {
            array[i].name = "";
    } 
    if(array[i].value == null) {
            array[i].value = ""; 
    }
}

How to make if condition all item of the array?

for (var i in array) {

    if(array[i] == null) {
        array[i] = "";
    } 

}

I tried this but the result is error on JavaScript.

array[i]name is not going to work. Why don't you fix that first. Just out of curiosity, why do want to replace null with an empty string? — user663031
– user663031, Commented Feb 20, 2017 at 3:06
@torazaburo on my ajax result thats works for me, but i have randomly null value from database, i want to convert it to empty string for my web view — wisnuaryadipa
– wisnuaryadipa, Commented Feb 20, 2017 at 3:22

Abdennour TOUMI · Accepted Answer · 2017-02-20 03:27:20Z

2

array.map(({name, value}) => ({
   name : (name === null) ? "" : name,
   value : (value === null) ? "" : value    
}))

Assuming you are checking equality EXACTLY with null (not undefined or false or something else),That's why we are using x === null instead of !x.

const array = [
  {name: "Something", value: null},
  {name: "SomethingB", value: "ValB"},
  {name: null, value: "ValC"},
]
   
 console.log(  
    array.map(({name, value}) => ({
       name : (name === null) ? "" : name,
       value : (value === null) ? "" : value    
    }))
    
)

edited Feb 20, 2017 at 3:27

answered Feb 20, 2017 at 3:03

Abdennour TOUMI

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Comments

Abhinav Galodha · Accepted Answer · 2017-02-20 03:16:34Z

0

One another implementation using the || operator, which can be used to set the default values.

To set default values using the ||, you can use code like

var value = expressionToEvaluate || defaultValue;

If expressionToEvaluate is falsey, then the value would be assigned the defaultValue. It would be useful to know about the falsey value in Javascript.

Complete working code:

var array = [{name: "parameter-name1", value: null},
  {name: null, value: "parameter-value2"},
  {name: null, value: null }
];


array.forEach(x => { x.name = x.name || "";
                     x.value = x.value || ""});

console.log(array);

answered Feb 20, 2017 at 3:16

Abhinav Galodha

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2 Comments

Abdennour TOUMI Over a year ago

NOPE.. (a || b) works with 6 cases 👉🏼 null , undefined, false, 0 , empty string OR not owned property.. However the question is exactly about null.

Abhinav Galodha Over a year ago

I agree that's the reason in the answer, i have also written about the falsey values.

user663031 · Accepted Answer · 2017-02-20 03:27:37Z

0

To apply the transformation from null to empty string on all properties, in place (mutating the original array):

for (let i = 0; i < array.length; i++) {
  const elt = array[i];

  for (let prop in elt) {
    if (elt[prop] === null) elt[prop] = '';
  }

}

Note that we are not using in to loop over elements in the array, as that is generally considered bad practice.

answered Feb 20, 2017 at 3:27

user663031

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