Add run-affected script

scripts/run-affected.js

@@ -0,0 +1,29 @@
+const { execSync } = require("child_process")
+
+const argv = require("yargs").demandOption([
+  "task",
+  "since",
+  "package-name",
+]).argv
+
+const { task, since, packageName } = argv
+
+const affectedPackages = execSync(
+  `yarn --silent lerna ls --since=${since} --json`,
+  {
+    encoding: "utf-8",
+  }
+)
+
+const packages = JSON.parse(affectedPackages)
+
+const isAffected = packages.some(pkg => pkg.name === packageName)
+
+if (isAffected) {
+  console.log(`${packageName} is affected. Running ${task}...`)
+  execSync(`yarn ${task} --scope=${packageName}`, {
+    stdio: "inherit",
+  })
+} else {
+  console.log(`${packageName} is not affected. Skipping ${task}...`)
+}