refactor: safeMerge()

lib/safe-merge.js

@@ -34,34 +34,23 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 const merge = require('lodash/merge');
 
-const map = require('lodash/map');
+function safeMerge() {
+  const args = Array.from(arguments);
+  const data = merge({}, ...args.map(arg => arg.data));
+  const time = args.reduce(
+    (maxTime, arg) => ((arg.time || 0) > maxTime ? arg.time : maxTime),
+    0
+  );
+  const source = args.reduce((acc, arg) => {
+    if (arg.source) {
+      // NOTE: multiple source might not even exists. Tests contain only one source in each argument
+      Array.isArray(arg.source)
+        ? (acc = [...acc, ...arg.source])
+        : acc.push(arg.source);
+    }
+    return acc;
+  }, []);
 
-const max = require('lodash/max');
-
-const reduce = require('lodash/reduce');
-
-const filter = require('lodash/filter');
-
-function toArray(value) {
-  if (Array.isArray(value)) {
-    return value;
-  }
-
-  if (value != null) {
-    return [value];
-  } else {
-    return [];
-  }
-}
-
-function sourceList(result, source) {
-  return toArray(result).concat(toArray(source));
-}
-
-function safeMerge(...args) {
-  const data = merge({}, ...Array.from(map(args, 'data')));
-  const time = max(filter(map(args, 'time')));
-  const source = reduce(map(args, 'source'), sourceList);
   return {
     data,
     time,