Run results for: test for of and flatMap

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser: Chrome 125

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Test name	Executions per second
flatmap	852.2 Ops/sec
for of	1674.9 Ops/sec

Script Preparation code:

function generateMockTeamsWithData(records) {
    const mockData = [];

    for (let i = 0; i < records; i++) {
        const team = {
            teamName: `Team ${i}`,
            channels: []
        };

        // Generate a random number of channels per team (1 to 5)
        const channelCount = Math.floor(Math.random() * 5) + 1;
        for (let j = 0; j < channelCount; j++) {
            const channel = {
                channelName: `Channel ${j}`,
                messages: []
            };

            // Generate a random number of messages per channel (1 to 10)
            const messageCount = Math.floor(Math.random() * 10) + 1;
            for (let k = 0; k < messageCount; k++) {
                const message = {
                    positiveMessageCount: Math.floor(Math.random() * 5),
                    negativeMessageCount: Math.floor(Math.random() * 5),
                    neutralMessageCount: Math.floor(Math.random() * 5),
                    user: {
                        id: `user${Math.floor(Math.random() * 1000)}`
                    }
                };
                channel.messages.push(message);
            }
            team.channels.push(channel);
        }
        mockData.push(team);
    }

    return mockData;
}

// Usage
var teamsWithData = generateMockTeamsWithData(1000);

Tests:

flatmap
function testFlatMap(teams) { const flatMessages = teams.flatMap((team) => team.channels.flatMap((channel) => channel.messages)); let totalPositiveCount = 0; let totalNegativeCount = 0; let totalNeutralCount = 0; const uniqueUserIds = new Set(); for (const message of flatMessages) { totalPositiveCount += message.positiveMessageCount; totalNegativeCount += message.negativeMessageCount; totalNeutralCount += message.neutralMessageCount; uniqueUserIds.add(message.user.id ?? ''); } return { totalPositiveCount, totalNegativeCount, totalNeutralCount, uniqueUserCount: uniqueUserIds.size }; } const result = testFlatMap(teamsWithData);
for of
// Test function function testForOfLoop(teams) { let totalPositiveCount = 0; let totalNegativeCount = 0; let totalNeutralCount = 0; const uniqueUserIds = new Set(); for (const team of teams) { for (const channel of team.channels) { for (const message of channel.messages) { totalPositiveCount += message.positiveMessageCount; totalNegativeCount += message.negativeMessageCount; totalNeutralCount += message.neutralMessageCount; uniqueUserIds.add(message.user.id ?? ''); } } } return { totalPositiveCount, totalNegativeCount, totalNeutralCount, uniqueUserCount: uniqueUserIds.size }; } const result2 = testForOfLoop(teamsWithData);

Run results for: test for of and flatMap

flatmap

for of