EC
TS2509
TypeScriptERRORNotableTypeHIGH confidence

Base constructor return type 'X' is not an object type or intersection of obj...

Production Risk

Build will fail; resolve before shipping.

What this means

A type-checking error (TS2509): Base constructor return type 'X' is not an object type or intersection of object types with statically known members.. This diagnostic is emitted by the TypeScript compiler when base constructor return type 'X' is not an object type or intersection of object types with statically known members..

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

TypeScript compiler reports TS2509 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS2509
// Base constructor return type 'X' is not an object type or intersection of object types with statically known members.

expected output

error TS2509: Base constructor return type 'X' is not an object type or intersection of object types with statically known members.

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