javascript count occurrences in array of objects code example

Example 1: array reduce and count based on proeperty js

const array = [
  {id: 12, name: 'toto'},
  {id: 12, name: 'toto'},
  {id: 42, name: 'tutu'},
  {id: 12, name: 'toto'},
];

const id = 12;
const count = array.filter((obj) => obj.id === id).length;

console.log(count);

Example 2: javascript count number of occurrences in array of objects

var result = array.reduce( (acc, o) => (acc[o.name] = (acc[o.name] || 0)+1, acc), {} );

Example 3: javascript count number of occurrences in array of objects

var array =
    [
        {"name":"abc","age":20}
        {"name":"abc","age":20}
        {"name":"abc","age":20}
        {"name":"xyz","age":21}
        {"name":"xyz","age":21}
    ]