Example of async generators with typescript

classFunc.ts

import { generateSequence } form './simple'

class NumberTransfrormer {
    transform = async function*(gen: AsyncGenerator<number>) {
        for await (const n of gen) {
            yield n * 2;
        }
    }
}

// run
(async () => {
    const multiplier = new HeaderFooterTransfrormer();
    for await (const value of multiplier.transform(multiplier.transform(generateSequence(1, 5)))) {
        console.log(value);
    }
})();

classMethod.ts

import { generateSequence } form './simple'

class NumberTransfrormer {
    async *transform(gen: AsyncGenerator<number>): AsyncGenerator<number> {
        for await (const n of gen) {
            yield n * 2;
        }
    }
}

// run
(async () => {
    const multiplier = new HeaderFooterTransfrormer();
    for await (const value of multiplier.transform(multiplier.transform(generateSequence(1, 5)))) {
        console.log(value);
    }
})();

simple.ts

export async function* generateSequence(start: number, end: number): AsyncGenerator<number> {
    for (let i = start; i <= end; i++) {
        await new Promise(resolve => setTimeout(resolve, 1000));
        yield i as number;
    }
}

// run
(async () => {
    for await (const value of generateSequence(1, 5)) {
        console.log(value); // 1, then 2, then 3, then 4, then 5
    }
})();