JSON array vs key-value JSON structure

Which json structure should I use for a list of objects (e.g. data about people), json array of objects or key-values where values are nested objects?

Array of objects

{
  "data":[
    {
      "name":"Dani",
      "age":23,
      "gender":"male"
    },
    {
      "name":"Jane",
      "age":30,
      "gender":"female"
    }
  ]

Key-values

{
  "data":{
    "Dani":{
      "age":23,
      "gender":"male"
    },
    "Jane":{
      "age":30,
      "gender":"female"
    }
  }
}