Add transform

transform.js

@@ -0,0 +1,49 @@
+import { reach } from './reach.js';
+
+/**
+ * Transform an object or collection to a different form.
+ *
+ * @param  {Object} source    The object to transform.
+ * @param  {Object} map       Object that describes how to transform the source: { [path.in.transformed.object]: [path.in.source] }.
+ * @return {Object}           A new object with the new structure.
+ */
+export const transform = (source, map) => {
+  const sep = '.';
+
+  if (Array.isArray(source)) {
+    const results = [];
+    for (let i = 0; i < source.length; ++i) {
+      results.push(transform(source[i], map));
+    }
+    return results;
+  }
+
+  const result = {};
+  const keys = Object.keys(map);
+
+  for (let i = 0, li = keys.length; i < li; ++i) {
+    const key = keys[i];
+    const path = key.split(sep);
+    const srcPath = map[key];
+
+    if (typeof srcPath !== 'string') {
+      console.warn('Transformation path invalid. Skipping.');
+      continue;
+    }
+
+    let segment;
+    let res = result;
+
+    while (path.length > 1) {
+      segment = path.shift();
+      if (!res[segment]) {
+        res[segment] = {};
+      }
+      res = res[segment];
+    }
+    segment = path.shift();
+    res[segment] = reach(srcPath, source);
+  }
+
+  return result;
+}