diff --git a/index.js b/index.js
index bfbe4ee..b1da3e9 100644
--- a/index.js
+++ b/index.js
@@ -1,24 +1,11 @@
 
 
-var functionOperators = [
-  'BETWEEN',
-  'IN',
-  /* ---- */
-  'OR',
-  'AND',
-  'EQ',
-  '=',
-  /* ---- */
-  'OR_BETWEEN',
-  'OR_IN',
-  /* ---- */
-  'AND_BETWEEN',
-  'AND_IN'
-];
 
 var functionOperatorMap = {
   BETWEEN: 'whereBetween',
   IN: 'whereIn',
+  ISNULL: 'whereNull',
+  NOTNULL: 'whereNotNull',
   /* ---- */
   OR: 'orWhere',
   AND: 'where',
@@ -27,9 +14,13 @@ var functionOperatorMap = {
   /* ---- */
   OR_BETWEEN: 'orWhereBetween',
   OR_IN: 'orWhereIn',
+  OR_ISNULL: 'orWhereNull',
+  IR_NOTNULL: 'orWhereNotNull',
   /* ---- */
   AND_BETWEEN: 'andWhereBetween',
-  AND_IN: 'andWhereIn'
+  AND_IN: 'andWhereIn',
+  AND_ISNULL: 'andWhereNull',
+  AND_NOTNULL: 'andWhereNotNull',
 };
 
 
@@ -43,7 +34,7 @@ function addCondition (q, field, val) {
   
   if (!Array.isArray(val)) {
     val = ['AND', field, val ];
-  } else if (functionOperators.indexOf(val[0]) !== -1) {
+  } else if (functionOperatorMap.hasOwnProperty( val[0] ) ) {
     val = [ val[0], field ].concat(val.slice(1));
   } else {
     val = [ 'AND', field ].concat(val);
diff --git a/package.json b/package.json
index c19697b..392c16b 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "knex-json-query",
-  "version": "0.0.3",
+  "version": "0.0.4",
   "description": "A high-level utility which will will generate Knex query from a single JSON object.",
   "main": "index.js",
   "scripts": {