🔰destructuring iterable

JS ⟩ operator ⟩ assignment ⟩ destructuring ⟩ iterable

let [a, ...rest] = "abc"    // rest = ['b', 'c']
for (const [i, value] of arr.entries()) { ... }

💾 程式：replit

// ⭐ works with any "iterable"
let [one, two, three] = new Set([1, 2, 3]);   // 1, 2, 3

// ⭐ "rest" (array)
let [a, b, ...rest] = "abcdef"     // a="a", b="b", rest=[ 'c', 'd', 'e', 'f' ]

// ----------------- ⭐ loop over key-value pairs -----------------

// 🔸 1. iterate over object properties
//  use `Object.entries()` for ordinary objects
for (let [key, value] of Object.entries(obj)) {
  log(`${key}: ${value}`);          // "name: John", "surname: Smith"
}

// 🔸 2. iterate over `Map`
for (let [key, value] of aMap) {
  log(`${key}: ${value}`);          // "name: John", "age: 30"
}
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