diff --git a/index.js b/index.js
index 5dcc3517..632fb00b 100644
--- a/index.js
+++ b/index.js
@@ -20,8 +20,9 @@ try {
 const addComma = `
   if (addComma) {
     json += ','
+  } else {
+    addComma = true
   }
-  addComma = true
 `
 
 function isValidSchema (schema, name) {
@@ -1247,39 +1248,52 @@ function nested (laterCode, name, key, location, subKey, isArray) {
         const nullIndex = type.indexOf('null')
         const sortedTypes = nullIndex !== -1 ? [type[nullIndex]].concat(type.slice(0, nullIndex)).concat(type.slice(nullIndex + 1)) : type
         sortedTypes.forEach((type, index) => {
+          const statement = index === 0 ? 'if' : 'else if'
           const tempSchema = Object.assign({}, schema, { type })
           const nestedResult = nested(laterCode, name, key, mergeLocation(location, { schema: tempSchema }), subKey, isArray)
-
-          if (type === 'string') {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(obj${accessor} === null || typeof obj${accessor} === "${type}" || obj${accessor} instanceof Date || typeof obj${accessor}.toISOString === "function" || obj${accessor} instanceof RegExp || (typeof obj${accessor} === "object" && Object.hasOwnProperty.call(obj${accessor}, "toString")))
-                ${nestedResult.code}
-            `
-          } else if (type === 'null') {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(obj${accessor} == null)
-              ${nestedResult.code}
-            `
-          } else if (type === 'array') {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(Array.isArray(obj${accessor}))
-              ${nestedResult.code}
-            `
-          } else if (type === 'integer') {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(Number.isInteger(obj${accessor}) || obj${accessor} === null)
-              ${nestedResult.code}
-            `
-          } else if (type === 'number') {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(isNaN(obj${accessor}) === false)
-              ${nestedResult.code}
-            `
-          } else {
-            code += `
-              ${index === 0 ? 'if' : 'else if'}(typeof obj${accessor} === "${type}")
-              ${nestedResult.code}
-            `
+          switch (type) {
+            case 'string': {
+              code += `
+                ${statement}(obj${accessor} === null || typeof obj${accessor} === "${type}" || obj${accessor} instanceof Date || typeof obj${accessor}.toISOString === "function" || obj${accessor} instanceof RegExp || (typeof obj${accessor} === "object" && Object.hasOwnProperty.call(obj${accessor}, "toString")))
+                  ${nestedResult.code}
+              `
+              break
+            }
+            case 'null': {
+              code += `
+                ${statement}(obj${accessor} == null)
+                  ${nestedResult.code}
+              `
+              break
+            }
+            case 'array': {
+              code += `
+                ${statement}(Array.isArray(obj${accessor}))
+                  ${nestedResult.code}
+              `
+              break
+            }
+            case 'integer': {
+              code += `
+                ${statement}(Number.isInteger(obj${accessor}) || obj${accessor} === null)
+                  ${nestedResult.code}
+              `
+              break
+            }
+            case 'number': {
+              code += `
+                ${statement}(isNaN(obj${accessor}) === false)
+                  ${nestedResult.code}
+              `
+              break
+            }
+            default: {
+              code += `
+                ${statement}(typeof obj${accessor} === "${type}")
+                  ${nestedResult.code}
+              `
+              break
+            }
           }
           laterCode = nestedResult.laterCode
         })