Actually continuously integrate

.github/actions/format/action.yml

@@ -0,0 +1,8 @@
+name: Format YAML files
+inputs:
+  token:
+    required: true
+    default: "${{ github.token }}"
+runs:
+  using: node20
+  main: index.js

.github/actions/format/index.js

@@ -0,0 +1,54 @@
+const core = require("@actions/core")
+const fs = require("fs")
+const yaml = require("js-yaml")
+
+try {
+  const yamlFiles = fs.readdirSync("./").filter(file => file.endsWith(".yaml"))
+  format(yamlFiles)
+} catch (error) {
+  core.setFailed(error.message)
+}
+
+function format(yamlFiles) {
+  yamlFiles.forEach(file => {
+    const content = fs.readFileSync(file)
+
+    let data = yaml.load(content)
+    data = consistent(data)
+    data = sort(data)
+
+    const formattedContent = yaml.dump(data, {quotingType: '"', lineWidth: -1})
+    fs.writeFileSync(file, formattedContent)
+  })
+}
+
+function consistent(data) { // one-record subdomains might not be an array
+  for (const key in data) {
+    if (!Array.isArray(data[key])) {
+      const array = [data[key]]
+      data[key] = array
+    }
+  }
+
+  return data
+}
+
+function sort(subdomains) {
+  const sortedSubdomains = {}
+  Object.keys(subdomains).sort().forEach(key => {
+    sortedSubdomains[key] = subdomains[key]
+  })
+
+  for (const subdomain in sortedSubdomains) {
+    const records = sortedSubdomains[subdomain]
+    for (const record in records) {
+      const sortedOptions = {}
+      Object.keys(records[record]).sort().forEach(option => {
+        sortedOptions[option] = sortedSubdomains[subdomain][record][option]
+      })
+      sortedSubdomains[subdomain][record] = sortedOptions
+    }
+  }
+
+  return sortedSubdomains
+}