데이터 타입 변경하기

  author: Dev.ian
  createdAt: 2024-05-28
  updatedAt: 2024-08-25

---

- Map -> Array

• example data

    // map
    const map: Map<string, string> = new Map<string, string>()
      .set('apple', 'ios')
      .set('google', 'android')
      .set('ms', 'windows');

Array.from()

• example code

    const arr = Array.from(map, ([name, os]) => ({name, os}));

• custom(Key 이름 지정)

    const arr = Array.from(map, ([key, value]) => ({name: key, os: value}));

    [{
      "name": "apple",
      "os": "ios"
    }, {
      "name": "google",
      "os": "android"
    }, {
      "name": "ms",
      "os": "windows"
    }] 

• custom

    const arr = Array.from(map, ([key, value]) => ({[key]: value}));

    [{
      "apple": "ios"
    }, {
      "google": "android"
    }, {
      "ms": "windows"
    }] 

[...]

• Array.from() 과 동일하게 사용 가능

    const arr = [...map].map(([name, os]) => ({name, os}));

    const arr = [...map].map(([key, value]) => ({name: key, os: value}));

    const arr = [...map].map(([key, value]) => ({[key]: value}));

---

- Set -> Array

• example data

    // set
    const companies: Set<string> = new Set<string>()
      .add('apple')
      .add('google')
      .add('ms');

Array.from()

  const arr = Array.from(companies);

  ["apple", "google", "ms"] 

[...]

  const arr = [...companies];

  ["apple", "google", "ms"] 

---

- Array -> Map

• example data

    // array
    const arr = ['apple', 'google', 'ms'];

• code

  • new Map<K,V>([[key1, value1], [key2, value2], ... , [keyN, valueN]])

    const map = new Map<string, number>(
      arr.map((item, idx) => [item, idx])
    );

    Map (3) {"apple" => 0, "google" => 1, "ms" => 2} 

- Array -> Set

• example data

    // array
    const arr = ['apple', 'google', 'ms'];

• code

  • new Set<T>([item1, item2, ... , itemN])

    const companies = new Set<string>(arr);

    Set (3) {"apple", "google", "ms"} 

---

• Refs:
  • StackOverflow-How to convert Map to array of object?