EC
TS6386
TypeScriptERRORNotableConfigHIGH confidence

Performance timings for '--diagnostics' or '--extendedDiagnostics' are not av...

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS6386): Performance timings for '--diagnostics' or '--extendedDiagnostics' are not available in this session. A native implementation of the Web Performance API could not be found.. This diagnostic is emitted by the TypeScript compiler when performance timings for '--diagnostics' or '--extendedDiagnostics' are not available in this session. A native implementation of the Web Performance API could not be found..

Why it happens
  1. 1The function overload signatures do not match the implementation
How to reproduce

TypeScript compiler reports TS6386 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS6386
// Performance timings for '--diagnostics' or '--extendedDiagnostics' are not available in this session. A native implementation of the Web Performance API could not be found.

expected output

error TS6386: Performance timings for '--diagnostics' or '--extendedDiagnostics' are not available in this session. A native implementation of the Web Performance API could not be found.

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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