EC
TS1064
TypeScriptERRORNotableSyntaxHIGH confidence

The return type of an async function or method must be the global Promise<T> ...

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1064): The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<X>'?. This diagnostic is emitted by the TypeScript compiler when the return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<X>'?.

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

TypeScript compiler reports TS1064 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1064
// The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<X>'?

expected output

error TS1064: The return type of an async function or method must be the global Promise<T> type. Did you mean to write 'Promise<X>'?

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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