1# Universal module definitions (UMD) are not supported 2 3Rule ``arkts-no-umd`` 4 5**Severity: error** 6 7ArkTS does not support universal module definitions (UMD) because in the 8language there is no concept of "script" (as opposed to "module"). 9Besides, in ArkTS import is a compile-time, not a runtime feature. 10Use ordinary syntax for ``export`` and ``import`` instead. 11 12 13## TypeScript 14 15 16``` 17 18 // math-lib.d.ts 19 export const isPrime(x: number): boolean 20 export as namespace mathLib 21 22 // in script 23 mathLib.isPrime(2) 24 25``` 26 27## ArkTS 28 29 30``` 31 32 // math-lib.d.ts 33 namespace mathLib { 34 export isPrime(x: number): boolean 35 } 36 37 // in program 38 import { mathLib } from "math-lib" 39 mathLib.isPrime(2) 40 41``` 42 43## See also 44 45- Recipe 129: Wildcards in module names are not supported (``arkts-no-module-wildcards``) 46 47 48