No properties in common TypeScript TS2559

Why This Happens

In TypeScript, two types have zero overlapping properties. This is one of the most common TypeScript errors developers encounter. Understanding the root cause helps you fix it quickly and prevent it from recurring.

The Problem

interface A { x: number; }
interface B { y: string; }
const obj: A = { y: 'test' } as A;

The Fix

interface A { x: number; }
const obj: A = { x: 1 };

Step-by-Step Fix

1. 1

   Identify the error

   Look at the error message: TS2559: Type has no properties in common. This tells you exactly what went wrong.

2. 2

   Find the cause

   Check the stack trace to find which line of your TypeScript code triggered this error.

3. 3

   Apply the fix

   Use the corrected code pattern shown above. Test to confirm the error is resolved.