EC
TS6048
TypeScriptERRORNotableConfigHIGH confidence

Locale must be of the form <language> or <language>-<territory>. For example ...

Production Risk

Build will fail; resolve before shipping.

What this means

A compiler configuration error (TS6048): Locale must be of the form <language> or <language>-<territory>. For example 'X' or 'X'.. This diagnostic is emitted by the TypeScript compiler when locale must be of the form <language> or <language>-<territory>. For example 'X' or '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 TS6048 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS6048
// Locale must be of the form <language> or <language>-<territory>. For example 'X' or 'X'.

expected output

error TS6048: Locale must be of the form <language> or <language>-<territory>. For example 'X' or '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

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

← All TypeScript errors