EC
TS1203
TypeScriptERRORNotableSyntaxHIGH confidence

Export assignment cannot be used when targeting ECMAScript modules. Consider ...

Production Risk

Build will fail; resolve before shipping.

What this means

A syntax error (TS1203): Export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead.. This diagnostic is emitted by the TypeScript compiler when export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead..

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

TypeScript compiler reports TS1203 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS1203
// Export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead.

expected output

error TS1203: Export assignment cannot be used when targeting ECMAScript modules. Consider using 'export default' or another module format instead.

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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