SF-PD2 User Interface Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  Use the toLocaleString() method on the JavaScript Number object inside the component's renderedCallback.

  Why it's wrong here

  toLocaleString() relies on the browser's locale, which in Lightning Experience is not guaranteed to match the Salesforce user's locale setting. In a German org accessed from an en-US browser, totals would render in US format, producing incorrect currency presentation. It also does not respect Salesforce locale, currency, or the org's default currency, so results diverge from server-side formatting.

• ✗

  Call the Apex method with a @AuraEnabled(cacheable=true) annotation and rely on Apex to return the formatted string.

  Why it's wrong here

  Apex runs in the system context and does not automatically localize numbers to the running user's locale. Returning a pre-formatted string from Apex hard-codes the format and breaks when the user changes locale. The cacheable annotation only affects client-side caching and does not influence formatting, so this approach produces incorrect display values.

• ✗

  Bind the raw numeric field from Apex directly into the template and let the browser's Intl.NumberFormat format it automatically.

  Why it's wrong here

  Lightning Web Component templates do not automatically run Intl.NumberFormat on interpolated values. Binding a raw number renders the unformatted JavaScript number, so no thousands separators or currency symbols appear. Formatting must be done explicitly in JavaScript before assigning the value to a property used in the template.

• ✓

  Import the formatNumber function from lightning/i18n and call it with the numeric value and the appropriate format string.

  Why this is correct

  lightning/i18n exposes formatNumber, which formats values according to the running user's Salesforce locale. This keeps the displayed total aligned with the user's language and region settings and matches how Salesforce formats numbers elsewhere. Using it avoids browser-locale drift and keeps formatting consistent across the org's users regardless of their OS or browser settings.