minimongo: support semi-logical $elemMatch

ie, a document with some logical operator and some equality in an
elemMatch.

eg: {a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}}

Fixes #1875.

History.md

@@ -3,6 +3,8 @@
 * Use "faye-websocket" (0.7.2) npm module instead of "websocket" (1.0.8) for
   server-to-server DDP.
 
+* minimongo: Support {a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}}  #1875
+
 
 ## v0.7.1.2
 

packages/minimongo/helpers.js

@@ -16,7 +16,10 @@ isIndexable = function (x) {
   return isArray(x) || isPlainObject(x);
 };
 
-isOperatorObject = function (valueSelector) {
+// Returns true if this is an object with at least one key and all keys begin
+// with $.  Unless inconsistentOK is set, throws if some keys begin with $ and
+// others don't.
+isOperatorObject = function (valueSelector, inconsistentOK) {
   if (!isPlainObject(valueSelector))
     return false;
 
@@ -26,7 +29,10 @@ isOperatorObject = function (valueSelector) {
     if (theseAreOperators === undefined) {
       theseAreOperators = thisIsOperator;
     } else if (theseAreOperators !== thisIsOperator) {
-      throw new Error("Inconsistent operator: " + valueSelector);
+      if (!inconsistentOK)
+        throw new Error("Inconsistent operator: " +
+                        JSON.stringify(valueSelector));
+      theseAreOperators = false;
     }
   });
   return !!theseAreOperators;  // {} has no operators

packages/minimongo/minimongo_tests.js

@@ -820,6 +820,12 @@ Tinytest.add("minimongo - selector_compiler", function (test) {
   nomatch({$or: [{a: 2}, {a: 3}], b: 2}, {a: 1, b: 2});
   nomatch({$or: [{a: 1}, {a: 2}], b: 3}, {a: 1, b: 2});
 
+  // Combining $or with equality
+  match({x: 1, $or: [{a: 1}, {b: 1}]}, {x: 1, b: 1});
+  match({$or: [{a: 1}, {b: 1}], x: 1}, {x: 1, b: 1});
+  nomatch({x: 1, $or: [{a: 1}, {b: 1}]}, {b: 1});
+  nomatch({x: 1, $or: [{a: 1}, {b: 1}]}, {x: 1});
+
   // $or and $lt, $lte, $gt, $gte
   match({$or: [{a: {$lte: 1}}, {a: 2}]}, {a: 1});
   nomatch({$or: [{a: {$lt: 1}}, {a: 2}]}, {a: 1});
@@ -1103,6 +1109,16 @@ Tinytest.add("minimongo - selector_compiler", function (test) {
   nomatch({a: {$elemMatch: {x: 5}}}, {a: {x: 5}});
   match({a: {$elemMatch: {0: {$gt: 5, $lt: 9}}}}, {a: [[6]]});
   match({a: {$elemMatch: {'0.b': {$gt: 5, $lt: 9}}}}, {a: [[{b:6}]]});
+  match({a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}},
+        {a: [{x: 1, b: 1}]});
+  match({a: {$elemMatch: {$or: [{a: 1}, {b: 1}], x: 1}}},
+        {a: [{x: 1, b: 1}]});
+  nomatch({a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}},
+          {a: [{b: 1}]});
+  nomatch({a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}},
+          {a: [{x: 1}]});
+  nomatch({a: {$elemMatch: {x: 1, $or: [{a: 1}, {b: 1}]}}},
+          {a: [{x: 1}, {b: 1}]});
 
   // $comment
   match({a: 5, $comment: "asdf"}, {a: 5});

packages/minimongo/selector.js

@@ -653,7 +653,7 @@ var ELEMENT_OPERATORS = {
         throw Error("$elemMatch need an object");
 
       var subMatcher, isDocMatcher;
-      if (isOperatorObject(operand)) {
+      if (isOperatorObject(operand, true)) {
         subMatcher = compileValueSelector(operand, matcher);
         isDocMatcher = false;
       } else {