Missing works with Merge and If, but it has to figure out whether it's given one array, or many scalars.

Author: jwadhams

logic.js

@@ -132,16 +132,17 @@ jsonLogic.apply = function(logic, data){
 			given one parameter, evaluate and return it.
 			given 0 parameters, return NULL
 		*/
-		while(values.length >= 2){
-			var conditional = jsonLogic.apply(values.shift(), data),
-				consequent = values.shift();
+		var v = values.slice(0); //Don't shift values off the original rule, destroy a copy
+		while(v.length >= 2){
+			var conditional = jsonLogic.apply(v.shift(), data),
+				consequent = v.shift();
 
 			if( jsonLogic.truthy(conditional) ){
 				return jsonLogic.apply(consequent, data);
 			}
 		}
 
-		if(values.length === 1) return jsonLogic.apply(values[0], data);
+		if(v.length === 1) return jsonLogic.apply(v[0], data);
 		return null;
 	}
 
@@ -161,6 +162,14 @@ jsonLogic.apply = function(logic, data){
 		return data;
 
 	}else if(op === "missing"){
+		/*
+			Missing can receive many keys as many arguments, like {"missing:[1,2]}
+			Missing can also receive *one* argument that is an array of keys,
+			which typically happens if it's actually acting on the output of another command 
+			(like IF or MERGE)
+		*/
+		if( Array.isArray(values[0]) ){ values = values[0]; }
+
 		var missing = [];
 		values.map(function(data_key){ 
 			if(jsonLogic.apply({'var':data_key}, data) === null){

tests/tests.js

@@ -46,7 +46,7 @@ QUnit.test( "Shared JsonLogic.com tests ", function( assert ){
 			assert.deepEqual(
 				jsonLogic.apply(rule, data), 
 				expected,
-				"jsonLogic("+ JSON.stringify(rule) +","+ JSON.stringify( data ) +") = " + expected
+				"jsonLogic("+ JSON.stringify(rule) +","+ JSON.stringify( data ) +") = " + JSON.stringify(expected)
 			);
 		}
 

tests/tests.json

@@ -87,11 +87,35 @@
 
 "Merge arrays",
 [{"merge":[]}, null, []],
-[{"merge":[["a"]]}, null, ["a"]],
-[{"merge":[["a"], ["b"]]}, null, ["a","b"]],
-[{"merge":[["a"], ["b"], ["c"]]}, null, ["a","b","c"]],
-[{"merge":[["a", "b"], ["c"]]}, null, ["a","b","c"]],
-[{"merge":[["a"], ["b", "c"]]}, null, ["a","b","c"]],
+[{"merge":[[1]]}, null, [1]],
+[{"merge":[[1],[]]}, null, [1]],
+[{"merge":[[1], [2]]}, null, [1,2]],
+[{"merge":[[1], [2], [3]]}, null, [1,2,3]],
+[{"merge":[[1, 2], [3]]}, null, [1,2,3]],
+[{"merge":[[1], [2, 3]]}, null, [1,2,3]],
+"Given non-array arguments, merge converts them to arrays",
+[{"merge":1}, null, [1]],
+[{"merge":[1,2]}, null, [1,2]],
+[{"merge":[1,[2]]}, null, [1,2]],
+
+"Missing and Merge, and If are friends. VIN is always required, APR is only required if financing is true.",
+[
+{"missing":{"merge":[
+	"vin", 
+	{"if": [{"var":"financing"}, ["apr"], [] ]}
+]} },
+{"financing":true},
+["vin","apr"]
+],
+
+[
+{"missing":{"merge":[
+	"vin", 
+	{"if": [{"var":"financing"}, ["apr"], [] ]}
+]} },
+{"financing":false},
+["vin"]
+],
 
 "END"
 ]