EC
TS1493
TypeScriptERRORNotableSyntaxHIGH confidence

The left-hand side of a 'for...in' statement cannot be a 'using' declaration.

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1493): The left-hand side of a 'for...in' statement cannot be a 'using' declaration.. This diagnostic is emitted by the TypeScript compiler when the left-hand side of a 'for...in' statement cannot be a 'using' declaration..

Why it happens
  1. 1Incorrect TypeScript syntax or type usage
  2. 2Type mismatch between declared and actual value
How to reproduce

TypeScript compiler reports TS1493 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1493
// The left-hand side of a 'for...in' statement cannot be a 'using' declaration.

expected output

error TS1493: The left-hand side of a 'for...in' statement cannot be a 'using' declaration.

Fix

Address the TypeScript diagnostic

WHEN When this error is reported by the compiler

Address the TypeScript diagnostic
// Run the TypeScript compiler for details:
npx tsc --noEmit
// Use the TypeScript playground to test your code:
// https://www.typescriptlang.org/play

Why this works

Review the full error message and location; the TypeScript handbook provides guidance on each error category.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev

← All TypeScript errors