count elements in list javascript code example
Example 1: use .map to count length of each element in an array
var lengths = chars.map(function(word){
return word.length
})
Example 2: JavaScript count list items
var myUL = document.getElementById("myUL");
var list = myUL.children.tags("LI");
alert(list.length);
Example 3: JavaScript count list items
var ul = document.getElementById("myul");
var liNodes = [];
for (var i = 0; i < ul.childNodes.length; i++) {
if (ul.childNodes[i].nodeName == "LI") {
liNodes.push(ul.childNodes[i]);
}
}
Example 4: typescript count array condition
let data = [ { "id": 1, "is_read": true, }, { "id": 2, "is_read": true, }, { "id": 3, "is_read": false, }, { "id": 4, "is_read": true, }, ],
length = data.filter(function(item){
return item.is_read;
}).length;
console.log(length)