map < Array < JavaScript

The map() method of an array creates a new array with the results of calling a function on every element in the array.

    
    const numbers = [2, 4, 6, 8];

    const numbersSquared = numbers.map(x => x * 2);

    console.log(numbersSquared);
    // [4, 8, 12, 16]


    // common, more-advanced example
    // in an array of objects, add several fields in a child object of the object
    const SUVs = [
        {"name": "Explorer",
         "costs": {
                "price": 49000,
                "weightTax": 1400,
                "gasTax": 2000
            }
        },
        {"name": "Escalade",
         "costs": {
                "price": 60000,
                "weightTax": 2200,
                "gasTax": 1400
            }
        },
        {"name": "Tahoe",
         "costs": {
                "price": 55000,
                "weightTax": 1700,
                "gasTax": 1300
            }
        }
    ]

    const SUVsTotalCost = SUVs.map((suv) => {
        SUVTotal = {};
        SUVTotal.name = suv.name;
        totalCost = suv.costs.price + suv.costs.weightTax + suv.costs.gasTax;
        SUVTotal.totalCost = totalCost.toLocaleString("en-US", {style:"currency", currency:"USD"});
        return SUVTotal;
    });

    console.log(SUVsTotalCost);
    [
      {name: "Explorer", totalCost: "$52,400.00"},
      {name: "Escalade", totalCost: "$63,600.00"},
      {name: "Tahoe", totalCost: "$58,000.00"}
    ]


    // common, more-advanced example
    const cars = [
      {"brand": "Ford", "color": "purple", "type": "minivan", "capacity": 7},
      {"brand": "Chrysler", "color": "red", "type": "sports car", "capacity": 2},
      {"brand": "Volkswagon", "color": "red", "type": "hatch back", "capacity": 4}
    ]

    const carsUpperCase = cars.map((car) => car.brand.toUpperCase());

    console.log(carsUpperCase);
    // ["FORD", "CHRYSLER", "VOLKSWAGON"]