レコード型を活用したTypeScriptの効率的なマッピング

type MyRecord = Record<string, number>;

const recordExample: MyRecord = {
    "apple": 10,
    "banana": 20
};

type FruitCounts = Record<string, number>;

const fruits: FruitCounts = {
    "apple": 5,
    "banana": 8
};

type FruitPrice = Record<'apple' | 'banana', number>;

const fruitPrices: FruitPrice = {
    apple: 1.5,
    banana: 0.75
};

// fruitPrices.orange = 1.0; // エラー: 'orange' は型 'FruitPrice' に存在しません

type MixedRecord = Record<'name' | 'age', string | number>;

const person: MixedRecord = {
    name: "Alice",
    age: 30
};

type DynamicRecord = Record;

const dynamicData: DynamicRecord = {
"isActive": true,
"isVerified": false
};

type DynamicRecord = Record<string, boolean>;

const dynamicData: DynamicRecord = {
    "isActive": true,
    "isVerified": false
};

type NumericRecord = Record<'key1' | 'key2', number>;
type StringRecord = { [K in keyof NumericRecord]: string };

const stringRecord: StringRecord = {
    key1: "10",
    key2: "20"
};

type UserStatus = Record<'active' | 'inactive', boolean>;

const statusUpdate: UserStatus = {
    active: true,
    inactive: false
};

// statusUpdate.deleted = true; // エラー: 'deleted' は型 'UserStatus' に存在しません

type ProductPrices = Record<'apple' | 'banana' | 'cherry', number>;

const prices: ProductPrices = {
    apple: 1.2,
    banana: 0.8,
    cherry: 2.5
};

type IndexRecord = Record;

const list: IndexRecord = {
0: "apple",
1: "banana",
2: "cherry"
};

// list[3] = "date"; // 3番目の要素を追加できます

type Operations = Record<'add' | 'subtract', (x: number, y: number) => number>;

const operations: Operations = {
    add: (x, y) => x + y,
    subtract: (x, y) => x - y
};

const result = operations.add(5, 3); // 8