JavaScript Continue Statement

Continue vs Break

for (let i = 1; i <= 3; i++) {
    if (i === 2) continue;
    console.log(i);
}
// Output: 1, 3

for (let i = 1; i <= 3; i++) {
    if (i === 2) break;
    console.log(i);
}
// Output: 1

for (let i = 0; i < 5; i++) {
    if (i % 2 === 0) continue;
    console.log(i); // odd numbers
}

let i = 0;
while (i < 5) {
    i++;
    if (i === 3) continue;
    console.log(i);
}

🔹 Continue in For Loops

Use continue to skip specific iterations based on conditions:

// Print only positive numbers
let numbers = [-2, -1, 0, 1, 2, 3];

for (let i = 0; i < numbers.length; i++) {
    if (numbers[i] <= 0) {
        continue; // Skip negative numbers and zero
    }
    console.log("Positive number:", numbers[i]);
}

🔹 Continue with Arrays

Skip processing certain array elements:

// Process only valid email addresses
let emails = ["[email protected]", "invalid-email", "[email protected]", "", "[email protected]"];

for (let email of emails) {
    // Skip empty strings or emails without @
    if (!email || !email.includes("@")) {
        console.log(`Skipping invalid: "${email}"`);
        continue;
    }
    
    console.log(`Processing: ${email}`);
    // Email processing logic would go here
}

🔹 Continue in While Loops

Be careful with continue in while loops - make sure to update the counter:

// Print even numbers from 1 to 10
let num = 0;

while (num < 10) {
    num++; // IMPORTANT: Increment before continue
    
    if (num % 2 !== 0) {
        continue; // Skip odd numbers
    }
    
    console.log(`Even number: ${num}`);
}

🔹 Practical Example: Data Filtering

Use continue to filter and process data:

// Process student grades, skip invalid entries
let students = [
    { name: "Alice", grade: 85 },
    { name: "", grade: 90 },        // Invalid: no name
    { name: "Bob", grade: -5 },     // Invalid: negative grade
    { name: "Charlie", grade: 92 },
    { name: "Diana", grade: 150 }   // Invalid: grade too high
];

console.log("Valid student grades:");

for (let student of students) {
    // Skip students with invalid data
    if (!student.name || student.grade < 0 || student.grade > 100) {
        console.log(`Skipping invalid entry: ${JSON.stringify(student)}`);
        continue;
    }
    
    // Process valid student
    let letterGrade = student.grade >= 90 ? 'A' : 
                     student.grade >= 80 ? 'B' : 
                     student.grade >= 70 ? 'C' : 'D';
    
    console.log(`${student.name}: ${student.grade} (${letterGrade})`);
}