How can I check If a nested array contains a value?

Question

So I have this array:

 var watchesArray = [
 {
 model: "FR 10", 
 image:"",
 url: "",
 price: 129.99,
 sports: ["Running", "Fitness"],
 touchScreen:false,
 GPS:false,
 heartRateMonitor:false,
 hrZoneTraining:false,
 },
 ];
 if(watchesArray[0].sports(contains a specific value or values){
 do something
 } else {
 dont do anything
 }

And all I want to do is check whether this watch has a specific sport and if it does then put it in an if statement so that I can do something with it.

How can I do this? Thanks

• Jared Farrish: It's just an array, even if it's "nested": watchesArray[0].sports.indexOf('Running') !== -1 Note that this returns 0 if it's the first index, so you have to check for -1 (which is "not found").
• An Phan: Have you tried Underscore?

Answer 1

Use Array.indexOf like bellow

if(watchesArray[0].sports.indexOf('Running') > -1){
 do somwthing
}

NOTE:- In case of if parents doesn't exist it'll throw error.

Answer 2

It's just an array, even if it's "nested":

if (watchesArray[0].sports.indexOf('Running') !== -1) ...

This returns 0 if it's the first index, so you have to check for -1 (which is "not found").

Note that IE7/8 did not support Array.prototype.indexOf(), but there are ways to polyfill that if needed.

Answer 3

There is no one simple function which supported in all browsers but you can write the following code:

function contains(a, obj) {
 var i = a.length;
 while (i--) {
 if (a[i] === obj) {
 return true;
 }
 }
 return false;
}

For more details you look in this answer How do I check if an array includes an object in JavaScript?

Answer 4

You can try indexof like this:

var watchesArray = [
 {
 model: "FR 10", 
 image:"",
 url: "",
 price: 129.99,
 sports: ["Running", "Fitness"],
 touchScreen:false,
 GPS:false,
 heartRateMonitor:false,
 hrZoneTraining:false,
 },
 ];
 if (watchesArray[0].sports.indexOf('hello') != -1){
 alert("exists");
 } else {
 alert("this index does not exist");
 }

for array in javascript you can always traverse using the key specified. if the key does not exists indexof will return 0 so it will go to the else part.

Answer 5

As Jared mentioned you can use Array.indexOf()

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

In your case it would mean

if(watchesArray[0].sports.indexOf(value) !== -1){
 do something
} else {
 dont do anything
}

I also provided you a little function to match multiple values: jsbin

Answer 6

Nowadays you can also use Includes.

if(watchesArray[0].sports.includes('Running'))
{
 // Exists
}
else{
 // Doesn't exist
}

This is not always supported though so check that you browser supports it.