Array of Objects -> filter keys or values by startsWith -> merge result to object

I have an array of objects:

let cars = [
  {
    "color_1": "purple",
    "color_2": "red",
    "type": "minivan",
    "capacity": 7,
    "all_colors": []
  },
  {
    "color_1": "blue",
    "color_2": "orange",
    "type": "station wagon",
    "capacity": 5,
    "all_colors": []
  }
]

I want to filter all keys (startsWith) "color…" and merge them into "all_colors" like this:

let cars = [
  {
    "color_1": "purple",
    "color_2": "red",
    "type": "minivan",
    "capacity": 7,
    "all_colors": ['purple', 'red']
  },
  {...}
]

I tried this:

var res = Object.keys(Object.assign({}, ...cars)).filter(v => v.startsWith('color'));
console.log(res)

but i need it for all objects and i don’t know how to add the results into "all_colors"?

>Solution :

You can do it like this:

let cars = [
  { "color_1": "purple", "color_2": "red", "type": "minivan" ,"capacity": 7, "all_colors": [] },
  { "color_1": "blue", "color_2": "orange", "type": "station wagon","capacity": 5, "all_colors": [] }
];

for (const car of cars) {
  const color_properties = Object.keys(car).filter((key) => key.startsWith('color'));
  car.all_colors = color_properties.map((color) => car[color]);
}

console.log(cars);