add diff script

scripts/diff.js

@@ -0,0 +1,34 @@
+const {spawnSync} = require('child_process')
+const inquirer = require('inquirer')
+const glob = require('glob')
+
+async function go() {
+  const files = glob
+    .sync('src/+(exercise|final)/*.+(js|ts|tsx)', {
+      ignore: ['*.d.ts'],
+    })
+    .map(f => f.replace(/^src\//, ''))
+  const {first} = await inquirer.prompt([
+    {
+      name: 'first',
+      message: `What's the first file`,
+      type: 'list',
+      choices: files,
+    },
+  ])
+  const {second} = await inquirer.prompt([
+    {
+      name: 'second',
+      message: `What's the second file`,
+      type: 'list',
+      choices: files.filter(f => f !== first),
+    },
+  ])
+
+  spawnSync(`git diff --no-index ./src/${first} ./src/${second}`, {
+    shell: true,
+    stdio: 'inherit',
+  })
+}
+
+go()