Focused Updates

Sometimes you want to run validation only for a specific field (e.g., on blur) or skip certain fields. Vest introduces the suite.focus() method for declarative control over execution flow.

Why Focus?

In a large form, re-validating the entire suite on every keystroke can be inefficient and annoying for the user (e.g., showing errors for fields they haven't touched yet). Focused updates allow you to:

• Validate on Blur: Run checks only for the field the user just left.
• Skip Expensive Tests: Temporarily bypass heavy async validations when they aren't needed.
• Improve Performance: Run only what's necessary.

Running Only Specific Fields

Use focus({ only: ... }) to restrict the run to specific fields.

// Run only the 'username' field tests
suite.focus({ only: 'username' }).run(formData);

// Run multiple fields
suite.focus({ only: ['username', 'password'] }).run(formData);

This is equivalent to using the only() hook inside the suite, but defined externally at runtime.

Skipping Fields

Use focus({ skip: ... }) to ignore specific fields.

// Run everything EXCEPT 'terms_of_service'
suite.focus({ skip: 'terms_of_service' }).run(formData);

Fluent Chain

focus returns a "runnable" interface, allowing you to chain it with afterEach or run.

suite
  .focus({ only: 'email' })
  .afterEach(res => updateUI(res))
  .run(formData);

Behavior notes

• Focused runs do not persist between calls. Each focus call applies only to the immediately following run.
• When focusing specific fields, schema validation is skipped for fields outside the focus scope, allowing targeted validation even if the full payload is invalid.