I'm a beginner at JavaScript and I'm trying to solve this problem without Object.keys() or any regex. I have a working solution but I'm wondering if there's a better way to call on the object key within the array while still looping. If anyone has a way to do this that's basic please let me know.
Problem: Create a function called keyCount which accepts two parameters, an array of objects, and a string. The function should return a number which is the number of times that key appears in the array of objects.
Expected Result:
countTimesOfKey([{name:"Sharon"}, {name: "Manish"},{lastName: "Terma"}], "name")) // 2
My Answer:
function countTimesOfKey(arr, str) {
let count = 0
for (let i in arr){
let test = arr[i]
let test2 = test[str]
if (test2 !== undefined){
count += 1
}
}
return count
}
You can use Array.filter to filter out the items in the array which have str as a property (by using Object.hasOwnProperty), then return the length of the resulting array:
function countTimesOfKey(arr, str) {
return arr.filter(e => e.hasOwnProperty(str)).length;
}
console.log(countTimesOfKey([{
name: "Sharon"
}, {
name: "Manish"
}, {
lastName: "Terma"
}], "name"))Of course, using Object.keys() and @Spectric's solution are way better than the one below, I just wanted to show that we can even more 'simplify' this.
We can use for...in to
return the result counterconst result = countTimesOfKey([{name:"Sharon"}, {name: "Manish"},{lastName: "Terma"}], "name");
console.log(result);
function countTimesOfKey(arr, name) {
let counter = 0;
for (a in arr) {
for (let k in arr[a]) {
if (k === name) {
counter++;
}
}
}
return counter;
}