feat: refactor and test tools steps utilities (#42693)

tools/challenge-helper-scripts/helpers/insert-erms.js

@@ -0,0 +1,30 @@
+// Update given value with markers (labels)
+const insertErms = (seedCode, erms) => {
+  if (!erms || erms.length <= 1) {
+    throw `erms should be provided`;
+  }
+
+  if (erms.length <= 1) {
+    throw `erms should contain 2 elements`;
+  }
+
+  const separator = '\n';
+  const lines = seedCode.split(separator);
+  const markerLabel = '--fcc-editable-region--';
+
+  // Generate a version of seed code with the erm markers
+  const newSeedCode = erms
+    .slice(0, 2)
+    .reduce((acc, erm) => {
+      if (Number.isInteger(erm)) {
+        acc.splice(erm, 0, markerLabel);
+      }
+
+      return acc;
+    }, lines)
+    .join(separator);
+
+  return newSeedCode;
+};
+
+exports.insertErms = insertErms;