Bits of .NET

🔄 Generators = Iterable Functions

Normal functions run completely. Generators pause and resume. Infinite lists, async flows, custom iteration.

📝 Generator Basics

// Generator function
function* numberGenerator() {
    yield 1;
    yield 2;
    yield 3;
}

// Using generator
const gen = numberGenerator();
console.log(gen.next()); // { value: 1, done: false }
console.log(gen.next()); // { value: 2, done: false }
console.log(gen.next()); // { value: 3, done: false }
console.log(gen.next()); // { value: undefined, done: true }

// For-of loop
for (const num of numberGenerator()) {
    console.log(num); // 1, 2, 3
}

// Spread operator
const numbers = [...numberGenerator()]; // [1, 2, 3]

// Infinite sequence
function* infiniteNumbers() {
    let i = 0;
    while (true) {
        yield i++;
    }
}

const infinite = infiniteNumbers();
console.log(infinite.next().value); // 0
console.log(infinite.next().value); // 1
console.log(infinite.next().value); // 2

// Fibonacci sequence
function* fibonacci() {
    let a = 0, b = 1;
    while (true) {
        yield a;
        [a, b] = [b, a + b];
    }
}

const fib = fibonacci();
console.log(fib.next().value); // 0
console.log(fib.next().value); // 1
console.log(fib.next().value); // 1
console.log(fib.next().value); // 2
console.log(fib.next().value); // 3

🎯 Advanced Generators

// Yield with return value
function* generatorWithReturn() {
    yield 1;
    yield 2;
    return 3; // Ends generator
}

const gen2 = generatorWithReturn();
console.log(gen2.next()); // { value: 1, done: false }
console.log(gen2.next()); // { value: 2, done: false }
console.log(gen2.next()); // { value: 3, done: true }

// Yield with next parameter
function* interactiveGenerator() {
    const input1 = yield 'First input?';
    const input2 = yield 'Second input?';
    return `You said: ${input1} and ${input2}`;
}

const interactive = interactiveGenerator();
console.log(interactive.next().value); // 'First input?'
console.log(interactive.next('Hello').value); // 'Second input?'
console.log(interactive.next('World').value); // 'You said: Hello and World'

// Async generators
async function* asyncGenerator() {
    yield await Promise.resolve(1);
    yield await Promise.resolve(2);
    yield await Promise.resolve(3);
}

for await (const value of asyncGenerator()) {
    console.log(value); // 1, 2, 3
}

// Generator Use Cases
- Infinite sequences
- Lazy evaluation
- State machines
- Async flows
- Data pagination

💡 Generator Tips

• Use for infinite sequences
• Use for lazy evaluation
• Use for state machines
• Use for async flows
• Use for data pagination