EC
TS1199
TypeScriptERRORNotableSyntaxHIGH confidence

Unterminated Unicode escape sequence.

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1199): Unterminated Unicode escape sequence.. This diagnostic is emitted by the TypeScript compiler when unterminated Unicode escape sequence..

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

TypeScript compiler reports TS1199 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1199
// Unterminated Unicode escape sequence.

expected output

error TS1199: Unterminated Unicode escape sequence.

Fix

Address the TypeScript diagnostic

WHEN When this error is reported by the compiler

Address the TypeScript diagnostic
// Run the TypeScript compiler for details:
npx tsc --noEmit
// Use the TypeScript playground to test your code:
// https://www.typescriptlang.org/play

Why this works

Review the full error message and location; the TypeScript handbook provides guidance on each error category.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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