JavaScript: How to count the number of objects with a certain value

29/12/2020 97 words One minute

Let’s say we have an array of people and we want to find out how many people are older than 30.

A simple way would be filtering the array first and then get its length.

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const people = [
    {
        id: 1,
        age: 15
    },
    {
        id: 2,
        age: 20
    },
        {
        id: 3,
        age: 40
    },
        {
        id: 4,
        age: 50
    },
]

const count = people.filter(x => x.age > 30).length

console.log(count) // 2