fcm_batch_test.js

function getMessages(count) {
    const messages = [];
    for (let i = 0; i < count; i++) {
        messages.push({
            topic: `test-topic-${i % 10}`,
        });
    }
    return messages;
}

async function testSend() {
    const messages = getMessages(1000);
    const start = Date.now();
    const promises = [];
    for (let i = 0; i < messages.length; i++) {
        promises.push(admin.messaging().send(messages[i]));
    }
    await Promise.all(promises);
    return Date.now() - start;
}

async function testSendAll() {
    const messages = getMessages(1000);
    const start = Date.now();
    const promises = [];
    for (let i = 0; i + 100 <= messages.length; i += 100) {
        const batch = messages.slice(i, i + 100);
        promises.push(admin.messaging().sendAll(batch));
    }
    await Promise.all(promises);
    return Date.now() - start;
}