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Severity: error
Category: type-check
Stage: Stage 1

Description

TypeScript namespace declarations are not valid SJS syntax. Namespaces are a TypeScript-specific module system predating ES modules and have no ECMAScript equivalent.

Use ES module import/export syntax.

Example

// ✗ error
namespace Utils {    // SJS-E012
  export function format(s: string): string { return s.trim() }
}

Fix

// ✓ correct — ES module
// utils.sjs
export function format(s: string): string {
  return s.trim()
}

// consumer.sjs
import { format } from "./utils.sjs"

Related codes

  • SJS-E010 — enum is also banned (use sum types)
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