Improve example with a `projection` which flattens the selected fields

examples/23_custom_query_language.html

@@ -72,7 +72,14 @@
       }
 
       if (projection) {
-        query = `_.map(${query}, item => _.pick(item, ${JSON.stringify(projection.fields)}))`
+        // It is possible to make a util function "pickFlat"
+        // and use that when building the query to make it more readable.
+        const fields = projection.fields.map(field => {
+          const name = _.last(field.split('.'))
+          return `  '${name}': _.get(item, '${field}')`
+        })
+
+        query = `_.map(${query}, item => ({\n${fields.join(',\n')}})\n)`
       }
 
       return query