EC
TS6108
TypeScriptERRORNotableConfigHIGH confidence

Longest matching prefix for 'X' is 'X'.

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS6108): Longest matching prefix for 'X' is 'X'.. This diagnostic is emitted by the TypeScript compiler when longest matching prefix for 'X' is 'X'..

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

TypeScript compiler reports TS6108 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS6108
// Longest matching prefix for 'X' is 'X'.

expected output

error TS6108: Longest matching prefix for 'X' is 'X'.

Fix

Fix the tsconfig.json option

WHEN When a compiler option is invalid or missing

Fix the tsconfig.json option
// tsconfig.json
{
  "compilerOptions": {
    // Review and correct the flagged option
  }
}
// Run: npx tsc --showConfig to see effective config

Why this works

TypeScript validates tsconfig.json options; check the official tsconfig reference for valid values.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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