1var result = array.reduce( (acc, o) => (acc[o.name] = (acc[o.name] || 0)+1, acc), {} );
2

1var array =
2    [
3        {"name":"abc","age":20}
4        {"name":"abc","age":20}
5        {"name":"abc","age":20}
6        {"name":"xyz","age":21}
7        {"name":"xyz","age":21}
8    ]
9