I have an Object in the Arrays 0' th element as follows,

Array = {CreatedById: "Created By ID",CreatedDate: "Created Date",Id: 
"Record ID",IsDeleted: "Deleted",LastActivityDate: "Last Activity 
Date",LastModifiedById: "Last Modified By ID",LastModifiedDate: "Last 
Modified Date",Name: "Data Import Name",OwnerId: "Owner ID",SystemModstamp: 
"System Modstamp",Last_Name__c: "Last Name",Mandate_Date_Signed__c: "Mandate 
Date Signed",Mandate_End_Date__c: "Mandate End Date",Mandate__c: "Mandate"}

I'll need to check whether a key is available in the above array. I have used the includes() function like Array.includes('Last Name'). But it always return false. Did I miss anything? I'll need to check the key in the whole array even in key or value. Any modification to check the key in the Object?

I have an Object in the Arrays 0' th element as follows,

Array = {CreatedById: "Created By ID",CreatedDate: "Created Date",Id: 
"Record ID",IsDeleted: "Deleted",LastActivityDate: "Last Activity 
Date",LastModifiedById: "Last Modified By ID",LastModifiedDate: "Last 
Modified Date",Name: "Data Import Name",OwnerId: "Owner ID",SystemModstamp: 
"System Modstamp",Last_Name__c: "Last Name",Mandate_Date_Signed__c: "Mandate 
Date Signed",Mandate_End_Date__c: "Mandate End Date",Mandate__c: "Mandate"}

I'll need to check whether a key is available in the above array. I have used the includes() function like Array.includes('Last Name'). But it always return false. Did I miss anything? I'll need to check the key in the whole array even in key or value. Any modification to check the key in the Object?

• javascript
• arrays

Share Improve this question Follow edited Oct 4, 2018 at 6:57 Mamun 69k99 gold badges5151 silver badges6262 bronze badges asked Oct 4, 2018 at 5:29 HariprasathHariprasath 53911 gold badge1010 silver badges2121 bronze badges 13

• I have an array as follows, Array = if you did that, then Array.includes will fail - you aren't overwriting the javascript Array object are you? – Jaromanda X Commented Oct 4, 2018 at 5:31
• 8 That is not an array. It is an object. – Akrion Commented Oct 4, 2018 at 5:31
• @JaromandaX even if he did, it would still fail. – Patrick Roberts Commented Oct 4, 2018 at 5:31
• Huh @PatrickRoberts? I said Array.includes will fail ... not return false ... but will fail - oh, you mean "even if he didn't" [overwrite Array] - yeah, I know that, because it's not an Array – Jaromanda X Commented Oct 4, 2018 at 5:32
• 2 @JaromandaX Actually overwriting the global Array wouldn't make instance.includes(…) fail, but of course this snippet is not creating an array instance. – Bergi Commented Oct 4, 2018 at 5:34

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5 Answers 5

Sorted by: Reset to default 2

Array.prototype.includes()

The includes() method determines whether an array includes a certain element, returning true or false as appropriate.

Object.keys()

The Object.keys() method returns an array of a given object's own property names, in the same order as we get with a normal loop.

Since the object is not array, you can use Object.keys() to get an array of all the keys. The key you are trying to match is Last_Name__c not Last Name:

var obj = {
CreatedById: "Created By ID",CreatedDate: "Created Date",Id: 
"Record ID",IsDeleted: "Deleted",LastActivityDate: "Last Activity Date",LastModifiedById: "Last Modified By ID",LastModifiedDate: "Last Modified Date",Name: "Data Import Name",OwnerId: "Owner ID",SystemModstamp: "System Modstamp",Last_Name__c: "Last Name",Mandate_Date_Signed__c: "Mandate Date Signed",Mandate_End_Date__c: "Mandate End Date",Mandate__c: "Mandate"};
var res = Object.keys(obj).includes('Last_Name__c');
console.log(res);

The method you're looking for is hasOwnProperty, which is a native method of the JS Object type. Like so:

let array = {
    CreatedById: "Created By ID",
    CreatedDate: "Created Date",
    Id: "Record ID",
    IsDeleted: "Deleted",
    LastActivityDate: "Last Activity Date",
    LastModifiedById: "Last Modified By ID",
    LastModifiedDate: "Last Modified Date",
    Name: "Data Import Name",
    OwnerId: "Owner ID",
    SystemModstamp: "System Modstamp",
    Last_Name__c: "Last Name",
    Mandate_Date_Signed__c: "Mandate Date Signed",
    Mandate_End_Date__c: "Mandate End Date",
    Mandate__c: "Mandate"
}

console.log(array.hasOwnProperty('CreatedById') ? 'True' : 'False'); // Outputs True
console.log(array.hasOwnProperty('OtherProperty') ? 'True' : 'False'); // Outputs False

Check out the documentation for the method as well as the JS Object type.

The fault I made is, I got a Map response from the back end and assign it to a List attribute in the front end that's why I got the response as an Object Array like in the question.

Now I have changed the front-end attribute type as Map and checked as follows,

if(Object.keys(Array).includes(KEY) || Object.values(Array).includes(key))

and it works according to the Mamun's Answer.

var mainArray = [
{
	CreatedById: "Created By ID",
	CreatedDate: "Created Date",
	Id: "Record ID",
	IsDeleted: "Deleted",
	LastActivityDate: "Last Activity Date",
	LastModifiedById: "Last Modified By ID",
	LastModifiedDate: "Last Modified Date",
	Name: "Data Import Name",
	OwnerId: "Owner ID",
	SystemModstamp: "System Modstamp",
	Last_Name__c: "Last Name",
	Mandate_Date_Signed__c: "Mandate Date Signed",
	Mandate_End_Date__c: "Mandate End Date",
	Mandate__c: "Mandate"
}]


function find(array,searchKey,searchValue, match=false ){
    const findData = array.find(item=>!match ? item[searchKey] ===searchValue : item[searchKey].search(searchValue)>-1);

    return findData ? true : false

}

console.log('search exact `Data Import Name` => ',find(mainArray , 'Name', 'Data Import Name'));
console.log('search exact `Data` => ',find(mainArray , 'Name', 'Data'));
console.log('search contains `Data` => ', find(mainArray , 'Name', 'Data', true));
console.log('search contains `majid` => ', find(mainArray , 'Name', 'majid', true))




var obj = {
	CreatedById: "Created By ID",
	CreatedDate: "Created Date",
	Id: "Record ID",
	IsDeleted: "Deleted",
	LastActivityDate: "Last Activity Date",
	LastModifiedById: "Last Modified By ID",
	LastModifiedDate: "Last Modified Date",
	Name: "Data Import Name",
	OwnerId: "Owner ID",
	SystemModstamp: "System Modstamp",
	Last_Name__c: "Last Name",
	Mandate_Date_Signed__c: "Mandate Date Signed",
	Mandate_End_Date__c: "Mandate End Date",
	Mandate__c: "Mandate"
}
console.log(Reflect.get(obj ,'Name') ? true : false)
console.log(Reflect.get(obj ,'other') ? true : false)

I'm not sure if this is a correct way.

JSON.stringify(obj).includes(key)