Add snap after-package repack script

scripts/util.ts

@@ -0,0 +1,29 @@
+import { spawn, ChildProcess } from 'child_process'
+
+export async function exec(cmd: string, args: string[] = []) {
+  const child = spawn(cmd, args, { shell: true })
+  redirectOutputFor(child)
+  await waitFor(child)
+}
+
+function redirectOutputFor(child: ChildProcess) {
+  const printStdout = (data: Buffer) => {
+    process.stdout.write(data.toString())
+  }
+  const printStderr = (data: Buffer) => {
+    process.stderr.write(data.toString())
+  }
+  child.stdout.on('data', printStdout)
+  child.stderr.on('data', printStderr)
+
+  child.once('close', () => {
+    child.stdout.off('data', printStdout)
+    child.stderr.off('data', printStderr)
+  })
+}
+
+async function waitFor(child: ChildProcess) {
+  return new Promise((resolve) => {
+    child.once('close', () => resolve())
+  })
+}