valchecker

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API Overview ​

This reference documents the complete public API of valchecker. Each validation step is designed to be composable, type-safe, and runtime-focused.

Import Strategies ​

Valchecker provides two ways to import validation steps:

All Steps (Convenience) ​

ts
import { allSteps, createValchecker } from 'valchecker'

const v = createValchecker({ steps: allSteps })

Bundles every built-in step into your valchecker instance. Best for:

  • Rapid prototyping
  • CLI tools
  • Applications where bundle size isn't critical

Selective Imports (Tree-Shaking) ​

ts
import { createValchecker, number, object, string } from 'valchecker'

const v = createValchecker({ steps: [string, number, object] })

Import only what you need for optimal bundle size. Recommended for:

  • Production web applications
  • Libraries shipped to npm
  • Any size-sensitive deployment

API Categories ​

CategoryDescription
PrimitivesBase validators for strings, numbers, booleans, literals, and nullish types
StructuresHigher-level builders for objects, arrays, unions, intersections, and records
TransformsSteps that reshape data (trim, parse JSON, filter arrays, etc.)
Helpers & UtilitiesFlow control operations like check, transform, fallback, and use

Execution Model ​

Every schema exposes an execute() method that validates input and returns a result:

ts
const schema = v.object({
	title: v.string(),
	count: v.number(),
})

const result = await schema.execute({ title: 'Hello', count: 42 })

if (v.isSuccess(result)) {
	console.log(result.value) // { title: 'Hello', count: 42 }
}
else {
	console.error(result.issues) // Structured array of validation errors
}

Type Guards ​

  • v.isSuccess(result) - Narrows to { value: T }
  • v.isFailure(result) - Narrows to { issues: ExecutionIssue[] }

Reading the Docs ​

Each API page includes:

  1. Method signature - TypeScript interface
  2. Parameters - Required and optional configuration
  3. Return type - Inferred output type
  4. Issue codes - Possible validation failure codes
  5. Examples - Common usage patterns

Navigate to a specific category to explore all available steps: