EC
TS90029
TypeScriptERRORNotableConfigHIGH confidence

Add async modifier to containing function

Production Risk

Build will fail; resolve before shipping.

What this means

A TypeScript diagnostic (TS90029): Add async modifier to containing function. This diagnostic is emitted by the TypeScript compiler when add async modifier to containing function.

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

TypeScript compiler reports TS90029 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS90029
// Add async modifier to containing function

expected output

error TS90029: Add async modifier to containing function

Fix

Fix the tsconfig.json option

WHEN When a compiler option is invalid or missing

Fix the tsconfig.json option
// tsconfig.json
{
  "compilerOptions": {
    // Review and correct the flagged option
  }
}
// Run: npx tsc --showConfig to see effective config

Why this works

TypeScript validates tsconfig.json options; check the official tsconfig reference for valid values.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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