EC
TS6600
TypeScriptERRORNotableConfigHIGH confidence

Allow JavaScript files to be a part of your program. Use the 'checkJs' option...

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS6600): Allow JavaScript files to be a part of your program. Use the 'checkJs' option to get errors from these files.. This diagnostic is emitted by the TypeScript compiler when allow JavaScript files to be a part of your program. Use the 'checkJs' option to get errors from these files..

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

TypeScript compiler reports TS6600 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS6600
// Allow JavaScript files to be a part of your program. Use the 'checkJs' option to get errors from these files.

expected output

error TS6600: Allow JavaScript files to be a part of your program. Use the 'checkJs' option to get errors from these files.

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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