EC
TS1522
TypeScriptERRORNotableSyntaxHIGH confidence

A character class must not contain a reserved double punctuator. Did you mean...

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1522): A character class must not contain a reserved double punctuator. Did you mean to escape it with backslash?. This diagnostic is emitted by the TypeScript compiler when a character class must not contain a reserved double punctuator. Did you mean to escape it with backslash?.

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

TypeScript compiler reports TS1522 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1522
// A character class must not contain a reserved double punctuator. Did you mean to escape it with backslash?

expected output

error TS1522: A character class must not contain a reserved double punctuator. Did you mean to escape it with backslash?

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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