paulgalow · January 16, 2022 17:28 · Jan 16, 2022 · Jan 15, 2022
diff --git a/processManifest.js b/processManifest.js
@@ -0,0 +1,51 @@
+const dotenv = require("dotenv");
+const fs = require("fs").promises;
+const path = require("path");
+
+module.exports = async function processManifest(manifestData) {
+  const stageName = Object.keys(manifestData)[0];
+  const { outputs } = manifestData[stageName];
+  const envArray = outputs
+    .map((obj) => Object.values(obj))
+    .map((arr) => [camelToUpperSnakeCase(arr[0]), arr[1]]);
+  const envObject = Object.fromEntries(envArray);
+
+  const dotEnvFile = path.resolve(".env");
+  await updateDotEnv(dotEnvFile, envObject);
+};
+
+/* Utils, typically this would be a package includes from NPM */
+async function updateDotEnv(filePath, env) {
+  // Merge with existing values
+  try {
+    const existing = dotenv.parse(await fs.readFile(filePath, "utf-8"));
+    env = { ...existing, ...env };
+  } catch (err) {
+    if (err.code !== "ENOENT") {
+      throw err;
+    }
+  }
+
+  const contents = Object.keys(env)
+    .map((key) => format(key, env[key]))
+    .join("\n");
+  await fs.writeFile(filePath, contents);
+
+  return env;
+}
+
+function escapeNewlines(str) {
+  return str.replace(/\n/g, "\\n");
+}
+
+function format(key, value) {
+  return `${key}=${escapeNewlines(value)}`;
+}
+
+function camelToUpperSnakeCase(str) {
+  return [...str].reduce((previous, current) =>
+    current === current.toUpperCase()
+      ? (previous += "_" + current)
+      : (previous += current.toUpperCase())
+  );
+}