EC
TS6258
TypeScriptERRORNotableConfigHIGH confidence

'X' should be set inside the 'compilerOptions' object of the config json file

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS6258): 'X' should be set inside the 'compilerOptions' object of the config json file. This diagnostic is emitted by the TypeScript compiler when 'X' should be set inside the 'compilerOptions' object of the config json file.

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

TypeScript compiler reports TS6258 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS6258
// 'X' should be set inside the 'compilerOptions' object of the config json file

expected output

error TS6258: 'X' should be set inside the 'compilerOptions' object of the config json file

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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