EC
TS8020
TypeScriptERRORNotableStrictHIGH confidence

JSDoc types can only be used inside documentation comments.

Production Risk

Build will fail; resolve before shipping.

What this means

A strict mode error (TS8020): JSDoc types can only be used inside documentation comments.. This diagnostic is emitted by the TypeScript compiler when jSDoc types can only be used inside documentation comments..

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

TypeScript compiler reports TS8020 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS8020
// JSDoc types can only be used inside documentation comments.

expected output

error TS8020: JSDoc types can only be used inside documentation comments.

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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