Arseniy_Yurchenko
/
Home_work_2


			
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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>


    <script>

        //map и filter создают новый массив
        // sort //1

        let persons = [
            { name: "Иван", age: 17 },
            { name: "Мария", age: 35 },
            { name: "Алексей", age: 73 },
            { name: "Яков", age: 12 },
            { name: "А", age: 1 },
            { name: "Б", age: 5 },
            { name: "В", age: 3 },
            { name: "Г", age: 7 },

        ]

        function sort(array, keyName, reverse) {
            if (keyName === "age") {
                array.sort((a, b) => parseFloat(a.age) - parseFloat(b.age))
                if (reverse === false) {
                    array.sort((a, b) => parseFloat(b.age) - parseFloat(a.age))
                }
                console.log(array);
            }
            else if (keyName === "name") {
                array.sort((a, b) => a.name.localeCompare(b.name))
                if (reverse === false) {
                    array.sort((a, b) => b.name.localeCompare(a.name))
                }
                console.log(array);
            }
        }

        // array map //

        function returnInt(element) {
            if (typeof element === "string") {
                return parseInt(element, 10);
            } else {
                return element;
            }

        }


        console.log(["1", {}, null, undefined, "500", 700].map(returnInt))


        // array reduce //  

        function reducer(accumulator, currentValue) {
            if (typeof currentValue === "number") {
                return accumulator *= currentValue;
            };
            return accumulator

        }
        console.log(`array reduce = ${["0", 5, 3, "string", null].reduce(reducer, 1)}`); //единица задается 1му элементу  


        //  object filter //

        var phone = {
            brand: "meizu",
            model: "m2",
            ram: 2,
            color: "black",
        }

        // function filter(obj, func) {
        //     obj.key

        // }

        function filter(obj, func) {
            return Object.entries(obj).filter(e => func(...e)).reduce((a, [b, c] = b) => (a[b] = c, a), {})
        }
        console.log(filter(phone, (key, value) => key == "color" || value == 2))

        //  object map //

        function map(obj, func) {
            var object = {};
            for (var key in obj) {
                Object.assign(object, func(key, object[key])), delete object[key];;

            }
            return object;
        }

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


    </script>
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