EC
TS18009
TypeScriptERRORNotableTypeHIGH confidence

Private identifiers cannot be used as parameters.

Production Risk

Build will fail; resolve before shipping.

What this means

A TypeScript diagnostic (TS18009): Private identifiers cannot be used as parameters.. This diagnostic is emitted by the TypeScript compiler when private identifiers cannot be used as parameters..

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

TypeScript compiler reports TS18009 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS18009
// Private identifiers cannot be used as parameters.

expected output

error TS18009: Private identifiers cannot be used as parameters.

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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