Advanced 18 min read

Diagnosing Wire Errors and Deployment Failures

By the end of this lesson, you'll be able to:

  • Read the error property on a wired result to diagnose a failed call
  • Recognize common deployment failure causes
  • Distinguish a genuine AuraHandledException message from a generically stripped one

Prerequisites: "Salesforce Debug Logs and Apex Debugging"

Reading Wire Errors

@wire(getAccounts, { searchTerm: '$searchTerm' })
wiredAccounts(result) {
    this.wiredResult = result;
    if (result.error) {
        console.error('Wire failed:', result.error.body?.message);
    }
}

A failed wire doesn't throw — it populates the wired result's error property instead (Module 7). error.body?.message often contains the real AuraHandledException text (Module 7) if that's what the underlying Apex threw — but for a genuinely unexpected error, remember Module 7's exception-stripping behavior: the message may be generic rather than descriptive, by deliberate platform design, not a bug in the component.

Common Deployment Failures

  • Insufficient Apex test coverage (Module 14) — the platform's deployment coverage requirement isn't met.
  • A referenced field or object the target org doesn't have — a component or Apex class referencing something that exists in the source org but not (yet) in the deployment target.
  • A syntax error caught only at deploy-time validation — code that compiles fine standalone but fails the platform's own validation step during deployment.

A Worked Example

A component shows no data, and the console logs a wire error. Working through it:

  1. Is error.body.message an actual, specific AuraHandledException message (Module 7), or a generic one? A specific message usually points directly at the cause.
  2. Is the Apex method actually cacheable=true (Module 7)? A non-cacheable method used with @wire fails outright.
  3. Is a required parameter (like recordId) actually populated, or is it undefined because a reactive $-prefixed property (Module 6) was misspelled or never set?

Working through these in a fixed order, rather than guessing randomly, converges on the real cause faster.

Exercise

A wired Apex call shows an error with a generic, non-specific message rather than the custom text the Apex method's AuraHandledException was thrown with. Explain, as a comment, the likely reason.

Show hint

Recall Module 7's explanation of exception-stripping.

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Exercise

Challenge: a wire never fires at all, and no error appears either. What is a likely cause worth checking first?

Show hint

Recall Module 6's reactive parameter gotcha.

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Diagnosing Wire Errors and Deployment Failures Quiz

1. What happens on a wired result when the underlying call fails?

2. Why might error.body.message show a generic message instead of a custom AuraHandledException text?

3. Which of these is a common cause of a deployment failure?

4. What must be true of an Apex method for @wire to work with it?

5. What is a likely cause if a wire never fires and no error appears at all?

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Summary

A wired result carries its own error property to inspect directly, and most deployment failures trace back to a small, recognizable set of causes once you know what to look for.

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