Add infrastructure for setting up GraalVM.

src/constants.ts

@@ -0,0 +1,19 @@
+import * as otypes from '@octokit/types'
+import {homedir} from 'os'
+import {join} from 'path'
+
+export const IS_MACOS = process.platform === 'darwin'
+export const IS_WINDOWS = process.platform === 'win32'
+
+export const VERSION_LATEST = 'latest'
+export const VERSION_NIGHTLY = 'nightly'
+export const VERSION_TRUNK = 'trunk'
+
+export const GRAALVM_BASE = join(homedir(), '.graalvm')
+export const GRAALVM_FILE_EXTENSION = IS_WINDOWS ? '.zip' : '.tar.gz'
+export const GRAALVM_GH_USER = 'graalvm'
+export const GRAALVM_PLATFORM = IS_WINDOWS ? 'windows' : process.platform
+export const JDK_HOME_SUFFIX = IS_MACOS ? '/Contents/Home' : ''
+
+export type LatestReleaseResponse =
+  otypes.Endpoints['GET /repos/{owner}/{repo}/releases/latest']['response']