Run results for: run multiple iterations vs 1 iteration

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/145.0.0.0 Safari/537.36

Browser: Chrome 145

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: one month ago

Test name	Executions per second
multiple iterations	1087.7 Ops/sec
Single iteration	44302.6 Ops/sec

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

function randomHash() {
  return Math.random().toString(36).substring(2, 12);
}

function generateDataset(size) {
  const contactsToSync = [];
  const syncedContacts = [];

  const phoneHashes = [];
  const emailHashes = [];

  for (let i = 0; i < size; i++) {
    const phoneHash = randomHash();
    const emailHash = randomHash();

    phoneHashes.push(phoneHash);
    emailHashes.push(emailHash);

    contactsToSync.push({
      name: "Contact " + i,
      phoneNumberHashed: phoneHash,
      emailAddressHashed: emailHash,
    });
  }

  for (let i = 0; i < size; i++) {
    const usePhone = Math.random() > 0.5;

    syncedContacts.push({
      matched_by: {
        phone_hash: usePhone
          ? phoneHashes[Math.floor(Math.random() * size)]
          : undefined,
        email_hash: !usePhone
          ? emailHashes[Math.floor(Math.random() * size)]
          : undefined,
      },
      contact: {
        paytag: "user_" + i,
      },
    });
  }

  return { contactsToSync, syncedContacts };
}

var { contactsToSync, syncedContacts } = generateDataset(500);

Tests:

multiple iterations
/*When writing async/deferred tests, use `deferred.resolve()` to mark test as done*/ let matchedPhoneNumberHashes = []; let matchedEmailAddressHashes = []; let paytagToContactBookNameMap = {}; matchedPhoneNumberHashes = syncedContacts .map((contact) => contact.matched_by.phone_hash) .filter((item) => !!item); matchedEmailAddressHashes = syncedContacts .map((contact) => contact.matched_by.email_hash) .filter((item) => !!item); syncedContacts.forEach((syncedContact) => { const contactBookName = contactsToSync.find( (contact) => contact.phoneNumberHashed === syncedContact.matched_by.phone_hash || contact.emailAddressHashed === syncedContact.matched_by.email_hash, )?.name; if (contactBookName) { paytagToContactBookNameMap[syncedContact.contact.paytag] = contactBookName; } });
Single iteration
let matchedPhoneNumberHashes = []; let matchedEmailAddressHashes = []; let paytagToContactBookNameMap = {}; // Build fast lookup tables once let phoneHashToName = new Map(); let emailHashToName = new Map(); for (const contact of contactsToSync) { if (contact.phoneNumberHashed && !phoneHashToName.has(contact.phoneNumberHashed)) { phoneHashToName.set(contact.phoneNumberHashed, contact.name); } if (contact.emailAddressHashed && !emailHashToName.has(contact.emailAddressHashed)) { emailHashToName.set(contact.emailAddressHashed, contact.name); } } // Single pass over syncedContacts for (const syncedContact of syncedContacts) { const phoneHash = syncedContact.matched_by.phone_hash; const emailHash = syncedContact.matched_by.email_hash; if (phoneHash) matchedPhoneNumberHashes.push(phoneHash); if (emailHash) matchedEmailAddressHashes.push(emailHash); const contactBookName = (phoneHash ? phoneHashToName.get(phoneHash) : undefined) ?? (emailHash ? emailHashToName.get(emailHash) : undefined); if (contactBookName) { paytagToContactBookNameMap[syncedContact.contact.paytag] = contactBookName; } }

Run results for: run multiple iterations vs 1 iteration

multiple iterations

Single iteration