EC
TS2584
TypeScriptERRORNotableTypeHIGH confidence

Cannot find name 'X'. Do you need to change your target library? Try changing...

Production Risk

Build will fail; resolve before shipping.

What this means

A type-checking error (TS2584): Cannot find name 'X'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'.. This diagnostic is emitted by the TypeScript compiler when cannot find name 'X'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'..

Why it happens
  1. 1The variable, type, or namespace is not declared in scope
  2. 2A missing import or type declaration
How to reproduce

TypeScript compiler reports TS2584 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS2584
// Cannot find name 'X'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'.

expected output

error TS2584: Cannot find name 'X'. Do you need to change your target library? Try changing the 'lib' compiler option to include 'dom'.

Fix

Declare or import the missing name

WHEN When a variable or type is not in scope

Declare or import the missing name
// Add the missing import
import { MyType } from './my-module';
// Or declare the variable
const myVar: MyType = ...;

Why this works

TypeScript requires all names to be declared before use; add the missing declaration or import.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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