Refactor build scripts

Build/lib/process-line.js

@@ -0,0 +1,32 @@
+/* eslint-disable camelcase -- cache index access */
+
+/**
+ * If line is commented out or empty, return null.
+ * Otherwise, return trimmed line.
+ *
+ * @param {string} line
+ */
+module.exports.processLine = (line) => {
+  if (!line) {
+    return null;
+  }
+
+  const line_0 = line[0];
+
+  if (
+    line_0 === '#'
+    || line_0 === ' '
+    || line_0 === '\r'
+    || line_0 === '\n'
+    || line_0 === '!'
+  ) {
+    return null;
+  }
+
+  const trimmed = line.trim();
+  if (trimmed === '') {
+    return null;
+  }
+
+  return trimmed;
+};