EC
TS5023
TypeScriptERRORCommonConfigurationHIGH confidence

Unknown compiler option

What this means

A compiler option specified in the 'tsconfig.json' file is not a valid TypeScript compiler option.

Why it happens
  1. 1A typo in the name of a compiler option.
  2. 2The compiler option is from a newer version of TypeScript than the one being used.
  3. 3Including a property in 'compilerOptions' that is not a recognized setting.
How to reproduce

An invalid option in tsconfig.json.

trigger — this will error
trigger — this will error
{
  "compilerOptions": {
    "target": "es6",
    "strict": true,
    "strictmode": true // Typo for strict
  }
}

expected output

error TS5023: Unknown compiler option 'strictmode'. Did you mean 'strict'?

Fix 1

Correct the option name

WHEN The option is misspelled.

Correct the option name
{
  "compilerOptions": {
    "target": "es6",
    "strict": true
  }
}

Why this works

Using the correct name as documented by TypeScript.

Fix 2

Update TypeScript version

WHEN The option is valid but not supported by the current version.

Update TypeScript version
// Run in terminal:
// npm install typescript@latest

Why this works

Upgrading the TypeScript compiler to a version that recognizes the option.

What not to do

✕ Remove the option without understanding it

The option may be important for code quality or behavior, and its purpose should be understood before removal.

Sources
Official documentation ↗

microsoft/TypeScript src/compiler/diagnosticMessages.json

Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev

← All TypeScript errors