Validation interview questions

Build a small form that books either a one-way or return flight, with validation tying the two date fields together.

Implement a set of helper functions that report the primitive type of any JavaScript value.

Implement a function that checks whether an object satisfies a source schema of predicate validators.

Build a schema-driven form validator with composable per-field rules, cross-field checks, and async validators that report all errors.

Validate IPv4 dotted-quad and IPv6 addresses, handling octet ranges, leading zeros, and :: zero-group compression.

Implement a function that decides whether a value is empty across arrays, strings, objects, Maps, Sets, and primitives.

Build a wizard form with next/back navigation, per-step validation, and a progress indicator.

Implement a small schema library that validates primitives and flat object shapes with composable rules.

Build a tiny schema validation library that supports chainable min and max rules on primitive types.

Build a signup form that validates user details on submit and posts them to a back-end API.

Implement helpers that accurately identify non-primitive JavaScript values such as arrays, plain objects, dates, and maps.

Extend a tiny schema validator to handle nested object and array shapes plus optional fields.