Add undist script

package.json

@@ -19,6 +19,7 @@
     "build:extended": "tsx scripts/build.ts extended-json",
     "build": "tsx scripts/build.ts package",
     "dist": "tsx scripts/dist.ts",
+    "undist": "tsx scripts/undist.ts",
     "feature-init": "tsx scripts/feature-init.ts",
     "format": "npx prettier --write .",
     "schema:write": "npm run schema -- --out ./schemas/data.schema.json",

scripts/undist.ts

@@ -0,0 +1,77 @@
+import yargs from "yargs";
+import { fileURLToPath } from "node:url";
+import fs from "node:fs";
+import YAML from "yaml";
+
+const argv = yargs(process.argv.slice(2))
+  .scriptName("undist")
+  .usage("$0 path", "Generate .yml from .yml.dist", (yargs) =>
+    yargs.positional("path", {
+      type: "string",
+      describe: "Path to feature.yml.dist file",
+      demandOption: true,
+    }),
+  )
+  .option("add", {
+    alias: "a",
+    type: "array",
+    describe: "BCD keys to add to the feature.yml file",
+  })
+  .option("sort", {
+    alias: "s",
+    type: "boolean",
+    default: true,
+    describe: "Sort the compat_features array",
+  }).argv;
+
+// Support `path/to/feature.yml.dist`, `path/to/feature.yml`, or `path/to/feature`
+function getPaths(path: string): { yml: string; dist: string } {
+  let base = path;
+  if (path.endsWith(".yml.dist")) {
+    base = path.slice(0, -9);
+  } else if (path.endsWith(".yml")) {
+    base = path.slice(0, -4);
+  }
+  return {
+    yml: `${base}.yml`,
+    dist: `${base}.yml.dist`,
+  };
+}
+
+async function main() {
+  const { path, sort, add = [] } = argv;
+  // Accept `-a key1,key2,key3` as well as `-a key1 -a key2 -a key3`
+  const additions = add.flatMap((addition) => addition.split(","));
+
+  const { yml, dist } = getPaths(path);
+
+  // Load and parse the .yml file
+  const ymlContents = fs.readFileSync(yml, { encoding: "utf-8" });
+  const ymlData = YAML.parseDocument(ymlContents);
+
+  // Assert 'compat_features' doesn't already exist
+  if (ymlData && ymlData.has("compat_features")) {
+    throw new Error(
+      `The key 'compat_features' is already present in the file ${yml}`,
+    );
+  }
+
+  // Load and parse the .dist.yml file
+  const distContents = fs.readFileSync(dist, { encoding: "utf-8" });
+  const distData = YAML.parse(distContents);
+
+  const compatFeatures = distData.compat_features;
+  if (additions.length > 0) {
+    compatFeatures.push(...additions);
+  }
+  if (sort) compatFeatures.sort();
+
+  ymlData.set("compat_features", compatFeatures);
+
+  fs.writeFileSync(yml, ymlData.toString({ lineWidth: 0 }));
+  console.log(`Added keys to ${yml}`);
+}
+
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
+  await main();
+}