📘arr.forEach()

🚧 施工中

JS⟩ syntax ⟩ for loops ⟩ arr.forEach()

• to skip a case, use return.

• ⭐️ there's no way to break/continue in this method❗️

💾 程式

💾 程式：replit

let array = [1, 2, 3, 4, 5];

// ⭐️ skip a case with `return`
array.forEach(n => {
    if (n % 2 !== 0) return;        // ✅ use `return`
    console.log(n);                 // 2, 4
});

// ⭐️ skip cases with `filter()`
array
    .filter(n => n % 2 == 0)        // ✅ use `filter`
    .forEach(n => console.log(n));  // 2, 4aa

🧨 雷區

• replit：no break/continue in forEach()

let array = [1, 2, 3, 4, 5];

// ❌ can't use `break` in .forEach()
array.forEach(n => {
    if (n % 2 !== 0) break;    
    //               ^^^^^
    // ⛔ SyntaxError:
    //    "Illegal break statement"
});

// ❌ can't use `continue` in .forEach()
array.forEach(n => {
    if (n % 2 !== 0) continue;    
    //               ^^^^^^^^
    // ⛔ SyntaxError:
    //    "Illegal continue statement: no surrounding iteration statement"
});

📗 參考

• Using Continue in JavaScript forEach() - use return to skip a case

📘 手冊

• Array.prototype.forEach()

🚧

to do：

• break statement

• continue statement