TS2869
TypeScriptERRORNotableTypeHIGH confidence
Right operand of ?? is unreachable because the left operand is never nullish.
Production Risk
Build will fail; resolve before shipping.
What this means
A type-checking error (TS2869): Right operand of ?? is unreachable because the left operand is never nullish.. This diagnostic is emitted by the TypeScript compiler when right operand of ?? is unreachable because the left operand is never nullish..
Why it happens
- 1A code path that should return a value returns never instead, or vice versa
How to reproduce
TypeScript compiler reports TS2869 during type checking.
trigger — this will error
trigger — this will error
// Triggers TS2869 // Right operand of ?? is unreachable because the left operand is never nullish.
expected output
error TS2869: Right operand of ?? is unreachable because the left operand is never nullish.
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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