Javascript: object array, check if item has value

Question

given that I have the following script, how can I only count if the array item has the value defined, in the following scenario i get 3 because it counts the arrays, but how do I check if the actual array attribute of firstName or lastname is not empty, I want it to count if either first name or last name is populated.

var x = [{"firstName":"guest1fnamee","lastName":"guest1fnamee"},{"firstName":"guest2fnamee","lastName":"guest2lnamee"},{"firstName":"","lastName":""}] var noGuests = 0 for (a in x) { noGuests++ } alert(noGuests) 

update My application's javascript render engine is outdated and can't use filter's.

SpiderMonkey 1.8.5

Answer 1

You can just filter the array by item which item.firstName and item.lastName is not empty and get the length of the result array

var x = [{"firstName":"guest1fnamee","lastName":"guest1fnamee"},{"firstName":"guest2fnamee","lastName":"guest2lnamee"},{"firstName":"","lastName":""}] const result = x.filter(item => item.firstName && item.lastName).length; console.log(result);

Answer 2

If any of the firstName or lastName is populated then this will count. If you need both firstName and lastName then change the condition from || to &&.

var x = [{"firstName":"guest1fnamee","lastName":"guest1fnamee"},{"firstName":"guest2fnamee","lastName":"guest2lnamee"},{"firstName":"","lastName":""}] var noGuests = 0 for (a in x) { if (x[a]['firstName'] || x[a]['lastName']) { noGuests++ } } console.log(noGuests); 

Or can do so using forEach loop

var x = [{"firstName":"guest1fnamee","lastName":"guest1fnamee"},{"firstName":"guest2fnamee","lastName":"guest2lnamee"},{"firstName":"","lastName":""}] var noGuests = 0 x.forEach(x => { if (x.firstName || x.lastName) noGuests++; }) console.log(noGuests); 

Answer 3

function count_non_empty(collection) { return filter_non_empty(collection).length; } function filter_non_empty(collection) { return collection && collection.length && collection.filter(elem => (elem.firstName || '').trim() // <--- If firstName is empty or empty-like string || (elem.lastName || '').trim() // <--- If lastName is empty or empty-like string ) || []; } 

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Illustration

function count_non_empty(collection) { return filter_non_empty(collection).length; } function filter_non_empty(collection) { return collection && collection.length && collection.filter(elem => (elem.firstName || '').trim() // <--- If firstName is empty or empty-like string || (elem.lastName || '').trim() // <--- If lastName is empty or empty-like string ) || []; } let onlyLastName = { "firstName": "", "lastName": "SomeLastName" }; let onlyFirstName = { "firstName": "SomeFirstName", "lastName": "" }; let emptyLookingFirstName = { "firstName": " ", "lastName": "SomeLastName" }; let emptyLookingLastName = { "firstName": " SomeFIrstName ", "lastName": " " }; let havingBoth = { "firstName": "guest1fnamee", "lastName": "guest1fnamee" }; let notHavingAny = { "firstName": " ", "lastName": "" } let x = [{ "firstName": "guest1fnamee", "lastName": "guest1fnamee" }, { "firstName": "guest2fnamee", "lastName": "guest2lnamee" }, { "firstName": " ", "lastName": "" } ]; console.log("Count - x:", count_non_empty(x)); console.log("Count:", count_non_empty([onlyLastName, onlyFirstName, havingBoth])); console.log("Count:", count_non_empty([onlyLastName, onlyFirstName, havingBoth, emptyLookingFirstName])); console.log("Count:", count_non_empty([onlyLastName, onlyFirstName, havingBoth, emptyLookingLastName])); console.log("Count - Not Having Any:", count_non_empty([notHavingAny])); console.log("Count - Having Both:", count_non_empty([havingBoth])); console.log("Count - Not Having Any with Having Both:", count_non_empty([notHavingAny, havingBoth])); console.log("Count - Not Having Any with Empty Looking First Name:", count_non_empty([notHavingAny, emptyLookingFirstName])); console.log("Count - Not Having Any with Empty Looking Last Name:", count_non_empty([notHavingAny, emptyLookingLastName]));

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WYSIWYG => WHAT YOU SHOW IS WHAT YOU GET