feat: provide support for groupby

Signed-off-by: Muhammad Aaqil <aaqilcs102@gmail.com>

lib/connectors/memory.js

@@ -502,7 +502,41 @@ Memory.prototype._findAllSkippingIncludes = function(model, filter) {
     // limit/skip
     const skip = filter.skip || filter.offset || 0;
     const limit = filter.limit || nodes.length;
+    // groupBy
     nodes = nodes.slice(skip, skip + limit);
+    if (filter.groupBy) {
+      nodes = utils.groupBy(nodes, filter.groupBy);
+      const tempNodes = [];
+      Object.keys(nodes).forEach(nodeKey => {
+        let count = undefined;
+        const tempNode = {...nodes[nodeKey][0]};
+        if (filter.count) {
+          count = nodes[nodeKey].filter((obj) => {
+            const id = obj[filter.count];
+            return obj[filter.count] === id;
+          }).length;
+          tempNode.count = count;
+        }
+        if (filter.max) {
+          tempNode.max = Math.max(...nodes[nodeKey].map(o => o[filter.max]));
+        }
+        if (filter.min) {
+          tempNode.min = Math.min(...nodes[nodeKey].map(o => o[filter.min]));
+        }
+        if (filter.sum) {
+          tempNode.sum = nodes[nodeKey].reduce((accumulator, object) => {
+            return accumulator + object[filter.sum];
+          }, 0);
+        }
+        if (filter.avg) {
+          tempNode.avg = nodes[nodeKey].reduce((accumulator, object) => {
+            return accumulator + object[filter.avg];
+          }, 0);
+          tempNode.avg = tempNode.avg / nodes[nodeKey].length;
+        }
+      });
+      nodes = tempNodes;
+    }
   }
   return nodes;
 

lib/dao.js

@@ -1930,6 +1930,18 @@ DataAccessObject.find = function find(query, options, cb) {
             }
           }
 
+          const keys = Object.keys(data);
+          keys.forEach(key => {
+            if (
+              key.includes('sumOf') ||
+              key.includes('countOf') ||
+              key.includes('avgOf') ||
+              key.includes('minOf') ||
+              key.includes('maxOf')
+            ) {
+              obj.__data[key] = data[key];
+            }
+          });
           callback(null, obj);
         }
 

lib/utils.js

@@ -31,6 +31,7 @@ exports.idsHaveDuplicates = idsHaveDuplicates;
 exports.isClass = isClass;
 exports.escapeRegExp = escapeRegExp;
 exports.applyParentProperty = applyParentProperty;
+exports.groupBy = groupBy;
 
 const g = require('strong-globalize')();
 const traverse = require('traverse');
@@ -893,3 +894,16 @@ function applyParentProperty(element, parent) {
     });
   }
 }
+
+function groupBy(items, key) {
+  return items.reduce(
+    (result, item) => ({
+      ...result,
+      [item[key]]: [
+        ...(result[item[key]] || []),
+        item,
+      ],
+    }),
+    {},
+  );
+}

test/crud-with-options.test.js

@@ -272,6 +272,28 @@ describe('crud-with-options', function() {
       User.find({limit: 3});
     });
 
+    it('should allow filter with groupBy, count, max, min, sum & avg', function(done) {
+      User.find({
+        groupBy: ['vip'],
+        count: 'vip',
+        max: 'id',
+        min: 'id',
+        sum: 'id',
+        avg: 'id',
+      }, options, function(err, users) {
+        should.not.exist(err);
+        should.exist(users);
+        users.forEach(user => {
+          user.should.have.property('count', user.count);
+          user.should.have.property('max');
+          user.should.have.property('min');
+          user.should.have.property('sum');
+          user.should.have.property('avg');
+        });
+        done();
+      });
+    });
+
     it('should skip trailing undefined args', function(done) {
       User.find({limit: 3}, function(err, users) {
         should.exists(users);