117

down vote

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15

I am working with titanium ,

my code looks like as ,

var currentData = new Array();

if(currentData[index]!==""||currentData[index]!==null||currentData[index]!=='null')

{

Ti.API.info("is exists " + currentData[index]);

return true;

}

else

{

return false;

}

I am passing index to array currentData,

For non existing element , i am still not able to detect it using above code

javascript titanium titanium-mobile

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edited Oct 28 '12 at 10:09

suresh.g

2,53652053

asked Oct 28 '12 at 9:56

Pradeep

2,26732146

1

Your logic is wrong. You need conjunctions (&&) between the individual conditions. ? J. K. Oct 28 '12 at 9:59

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9 Answers

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oldest

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208

down vote

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Use typeof arrayName[index] === 'undefined'

i.e.

if(typeof arrayName[index] === 'undefined') {

// does not exist

}

else {

// does exist

}

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edited Feb 12 '15 at 5:56

answered Oct 28 '12 at 9:58

techfoobar

49.2k978102

3

+1, nice. You can also use if(arrayName[index] === 'undefined') as a shortcut ? AnchovyLegend Oct 8 '13 at 0:08

44

@AnchovyLegend no, you cannot! But you can use if(arrayName[index] === undefined). ? Denis V Nov 29 '13 at 15:01

10

this fails, if the item is there, but it's value is undefined; use this answer instead -> stackoverflow.com/questions/1098040/? ? Matus May 17 '14 at 21:25

as @Matus said, there is more explanation here, you should be aware on. ? S.Thiongane Aug 8 '14 at 8:47

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59

down vote

var myArray = ["Banana", "Orange", "Apple", "Mango"];

if (myArray.indexOf(searchTerm) === -1) {

console.log("element doesn't exist");

}

else {

console.log("element found");

}

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edited May 8 '17 at 8:12

Pere

66211441

answered Sep 12 '13 at 17:35

yeswanth

1,043716

2

Unfortunately, this one doesn't work in IE 7 and below. ? darksoulsong Oct 7 '14 at 15:21

2

This in my opinion is the best answer, by now IE 7 is not mainteined any more so it's not a problem. Although I will suggest to use the triple equals if(myArray.indexOf(searchTerm) === -1) ? Mauro Gava Sep 1 '16 at 2:49

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up vote

3

down vote

Consider the array a:

var a ={'name1':1, 'name2':2}

If you want to check if 'name1' exists in a, simply test it with in:

if('name1' in a){

console.log('name1 exists in a')

}else

console.log('name1 is not in a')

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answered Aug 16 '15 at 4:43

Amir

14515

3

"var a" is not an array object in your case, but a regular object. Should be var a = [ ... ]. I think this is what author needed. ? tomazahlin Dec 16 '15 at 13:10

This is how to check for the existence of a key in an object, not the presence of an index in an array. ? Beejamin Feb 2 '17 at 0:58

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3

down vote

This way is easiest one in my opinion.

var nameList = new Array('item1','item2','item3','item4');

// Using for loop to loop through each item to check if item exist.

for (var i = 0; i < nameList.length; i++) {

if (nameList[i] === 'item1')

{

alert('Value exist');

}else{

alert('Value doesn't exist');

}

And Maybe Another way to do it is.

nameList.forEach(function(ItemList)

{

if(ItemList.name == 'item1')

{

alert('Item Exist');

}

}

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edited Dec 31 '15 at 23:18

answered Dec 31 '15 at 23:07

AmJustSam

1648

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2

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I had to wrap techfoobar's answer in a try..catch block, like so:

try {

if(typeof arrayName[index] == 'undefined') {

// does not exist

}

else {

// does exist

}

}

catch (error){ /* ignore */ }

...that's how it worked in chrome, anyway (otherwise, the code stopped with an error).

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answered Aug 9 '13 at 14:00

Swiss Mister

1,46311127

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2

down vote

If elements of array are also simple objects or arrays, you can use some function:

// search object

var element = { item:'book', title:'javasrcipt'};

[{ item:'handbook', title:'c++'}, { item:'book', title:'javasrcipt'}].some(function(el){

if( el.item === element.item && el.title === element.title ){

return true;

}

});

[['handbook', 'c++'], ['book', 'javasrcipt']].some(function(el){

if(el[0] == element.item && el[1] == element.title){

return true;

}

});

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edited Jan 23 '15 at 11:25

answered Jan 22 '15 at 12:42

Yaroslav Fedoruk

10623

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up vote

2

down vote

you can simply use this:

var tmp = ['a', 'b'];

index = 3 ;

if( tmp[index]){

console.log(tmp[index] + '\n');

}else{

console.log(' does not exist');

}

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answered Jul 21 '15 at 15:23

Salar

2,2321831

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up vote

2

down vote

Simple way to check item exist or not

Array.prototype.contains = function(obj) {

var i = this.length;

while (i--)

if (this[i] == obj)

return true;

return false;

}

var myArray= ["Banana", "Orange", "Apple", "Mango"];

myArray.contains("Apple")

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answered Nov 23 '16 at 14:21

Suhail Ahmed

713

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up vote

1

down vote

If you use underscore.js then these type of null and undefined check are hidden by the library.

So your code will look like this -

var currentData = new Array();

if (_.isEmpty(currentData)) return false;

Ti.API.info("is exists " + currentData[index]);

return true;

It looks much more readable now.