Pika
/
homework


			
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							<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        //sort
        var persons = [
            { name: "Иван", age: 17 },
            { name: "Мария", age: 35 },
            { name: "Алексей", age: 73 },
            { name: "Яков", age: 12 },
        ]

        function sort(arr, key, boolean = true) {
            arr.sort(bool)
            function bool(a, b) {
                if (boolean) {
                    return (a[key] > b[key]) ? 1 : -1;
                }
                else {
                    return (a[key] < b[key]) ? 1 : -1;
                }
            }
            return arr;
        }

        sort(persons, "name")


        //array map
        let array = ["1", {}, null, undefined, "500", 700]
        let y = array.map(x => {
            let number = Number(x)
            return isNaN(x) ? x : number
        })
        console.log(y)

        //array reduce
        let array = ["0", 5, 3, "string", null]
        let result = array.reduce((a, b) =>
            typeof (b) === "number" ? a * b : a, 1
        )
        console.log(result);

        //object filter
        var phone = {
            brand: "meizu",
            model: "m2",
            ram: 2,
            color: "black",
        };
        filter(phone, (key, value) => key == "color" || value == 2);

        function filter(obj, key, value) {
            let newObj = {}
            for (let key in obj) {
                for (let value in obj) {
                    if (obj[key] == 2 && value == "color") {
                        newObj[key] = obj[key]
                        newObj[value] = obj[value]
                    }

                }
            }
            return newObj
        }

        //object map
        function map(obj, callback) {
            let result1 = {};
            for (let key in obj) {
                result1 = { ...result1, ...callback(key, obj[key]) }
            }
            return result1
        }

        let miniObj = map({ name: "Иван", age: 17 }, function (key, value) {
            var result = {};
            result[key + "_"] = value + "$";
            return result;
        })
        console.log(miniObj)

        //Sum
        function sum (min, max, step){
            if(max <= 0){
            return 0 
            }
            return sum (min +step, max -1, step) + min
        }
        console.log(sum(1,5,3))

    </script>
</body>

</html>