EC
TS2758
TypeScriptERRORNotableTypeHIGH confidence

Each member of the union type 'X' has signatures, but none of those signature...

Production Risk

Build will fail; resolve before shipping.

What this means

A type-checking error (TS2758): Each member of the union type 'X' has signatures, but none of those signatures are compatible with each other.. This diagnostic is emitted by the TypeScript compiler when each member of the union type 'X' has signatures, but none of those signatures are compatible with each other..

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

TypeScript compiler reports TS2758 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS2758
// Each member of the union type 'X' has signatures, but none of those signatures are compatible with each other.

expected output

error TS2758: Each member of the union type 'X' has signatures, but none of those signatures are compatible with each other.

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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