Hardened Run-time Prop Validation and Integrity Checks

Snippet

Hardened Run-time Prop Validation and Integrity Checks

TypeScript provides build-time safety, but run-time integrity is equally important, especially when dealing with data from external APIs or unsafe 'any' casts. Using a schema validator like Zod inside a Svelte reactive block ensures the component crashes early or handles errors gracefully if unexpected data is injected.

snippet.js
javascript
import { onMount } from 'svelte';
import { z } from 'zod';
 
const UserSchema = z.object({
  id: z.string().uuid(),
  role: z.enum(['admin', 'editor', 'viewer']),
  email: z.string().email()
});
 
export let userData;
 
$: {
  try {
    UserSchema.parse(userData);
  } catch (e) {
    console.error('Integrity violation:', e.errors);
    throw new Error('Critical component state corruption');
  }
}

svelte

Breakdown

UserSchema.parse(userData);

Validates the input against a strict schema, throwing an error on mismatch.

$: { ... }

Re-runs the validation every time the 'userData' prop changes to maintain continuous integrity.

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Hardened Run-time Prop Validation and Integrity Checks

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