EC
TS1356
TypeScriptERRORNotableSyntaxHIGH confidence

Did you mean to mark this function as 'async'?

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1356): Did you mean to mark this function as 'async'?. This diagnostic is emitted by the TypeScript compiler when did you mean to mark this function as 'async'?.

Why it happens
  1. 1await used outside an async function, or async/await return type mismatch
How to reproduce

TypeScript compiler reports TS1356 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1356
// Did you mean to mark this function as 'async'?

expected output

error TS1356: Did you mean to mark this function as 'async'?

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

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