diff --git a/JsonExcel.vue b/JsonExcel.vue
index fd04dd4..4f9b985 100644
--- a/JsonExcel.vue
+++ b/JsonExcel.vue
@@ -106,7 +106,7 @@ export default {
         return;
       }
 
-      let json = this.getProcessedJson(data, this.downloadFields);
+      let json = await this.getProcessedJson(data, this.downloadFields);
       if (this.type === "html") {
         // this is mainly for testing
         return this.export(
@@ -247,18 +247,21 @@ export default {
 		---------------
 		Get only the data to export, if no fields are set return all the data
 		*/
-    getProcessedJson(data, header) {
+    async getProcessedJson(data, header) {
       let keys = this.getKeys(data, header);
       let newData = [];
       let _self = this;
-      data.map(function (item, index) {
+      await data.reduce(async function (prev, current) {
+        await prev;
         let newItem = {};
         for (let label in keys) {
           let property = keys[label];
-          newItem[label] = _self.getValue(property, item);
+          newItem[label] = await _self.getValue(property, current);
         }
         newData.push(newItem);
-      });
+
+        return true;
+      }, []);
 
       return newData;
     },
@@ -291,7 +294,7 @@ export default {
       return parseData;
     },
 
-    getValue(key, item) {
+    async getValue(key, item) {
       const field = typeof key !== "object" ? key : key.field;
       let indexes = typeof field !== "string" ? [] : field.split(".");
       let value = this.defaultValue;
@@ -302,7 +305,7 @@ export default {
       else value = this.parseValue(item[field]);
 
       if (key.hasOwnProperty("callback"))
-        value = this.getValueFromCallback(value, key.callback);
+        value = await this.getValueFromCallback(value, key.callback);
 
       return value;
     },
@@ -335,9 +338,9 @@ export default {
       return this.parseValue(nestedItem);
     },
 
-    getValueFromCallback(item, callback) {
+    async getValueFromCallback(item, callback) {
       if (typeof callback !== "function") return this.defaultValue;
-      const value = callback(item);
+      const value = await callback(item);
       return this.parseValue(value);
     },
     parseValue(value) {
diff --git a/dist/vue-json-excel.cjs.js b/dist/vue-json-excel.cjs.js
index 48b0d55..6bff9d7 100644
--- a/dist/vue-json-excel.cjs.js
+++ b/dist/vue-json-excel.cjs.js
@@ -271,7 +271,7 @@ var script = {
         return;
       }
 
-      let json = this.getProcessedJson(data, this.downloadFields);
+      let json = await this.getProcessedJson(data, this.downloadFields);
       if (this.type === "html") {
         // this is mainly for testing
         return this.export(
@@ -412,18 +412,21 @@ var script = {
 		---------------
 		Get only the data to export, if no fields are set return all the data
 		*/
-    getProcessedJson(data, header) {
+    async getProcessedJson(data, header) {
       let keys = this.getKeys(data, header);
       let newData = [];
       let _self = this;
-      data.map(function (item, index) {
+      await data.reduce(async function (prev, current) {
+        await prev;
         let newItem = {};
         for (let label in keys) {
           let property = keys[label];
-          newItem[label] = _self.getValue(property, item);
+          newItem[label] = await _self.getValue(property, current);
         }
         newData.push(newItem);
-      });
+
+        return true;
+      }, []);
 
       return newData;
     },
@@ -456,7 +459,7 @@ var script = {
       return parseData;
     },
 
-    getValue(key, item) {
+    async getValue(key, item) {
       const field = typeof key !== "object" ? key : key.field;
       let indexes = typeof field !== "string" ? [] : field.split(".");
       let value = this.defaultValue;
@@ -467,7 +470,7 @@ var script = {
       else value = this.parseValue(item[field]);
 
       if (key.hasOwnProperty("callback"))
-        value = this.getValueFromCallback(value, key.callback);
+        value = await this.getValueFromCallback(value, key.callback);
 
       return value;
     },
@@ -500,9 +503,9 @@ var script = {
       return this.parseValue(nestedItem);
     },
 
-    getValueFromCallback(item, callback) {
+    async getValueFromCallback(item, callback) {
       if (typeof callback !== "function") return this.defaultValue;
-      const value = callback(item);
+      const value = await callback(item);
       return this.parseValue(value);
     },
     parseValue(value) {
@@ -619,7 +622,11 @@ var __vue_render__ = function() {
   return _c(
     "div",
     { attrs: { id: _vm.idName }, on: { click: _vm.generate } },
-    [_vm._t("default", [_vm._v(" Download " + _vm._s(_vm.name) + " ")])],
+    [
+      _vm._t("default", function() {
+        return [_vm._v(" Download " + _vm._s(_vm.name) + " ")]
+      })
+    ],
     2
   )
 };
diff --git a/dist/vue-json-excel.esm.js b/dist/vue-json-excel.esm.js
index 2d9535d..5d6d24a 100644
--- a/dist/vue-json-excel.esm.js
+++ b/dist/vue-json-excel.esm.js
@@ -269,7 +269,7 @@ var script = {
         return;
       }
 
-      let json = this.getProcessedJson(data, this.downloadFields);
+      let json = await this.getProcessedJson(data, this.downloadFields);
       if (this.type === "html") {
         // this is mainly for testing
         return this.export(
@@ -410,18 +410,21 @@ var script = {
 		---------------
 		Get only the data to export, if no fields are set return all the data
 		*/
-    getProcessedJson(data, header) {
+    async getProcessedJson(data, header) {
       let keys = this.getKeys(data, header);
       let newData = [];
       let _self = this;
-      data.map(function (item, index) {
+      await data.reduce(async function (prev, current) {
+        await prev;
         let newItem = {};
         for (let label in keys) {
           let property = keys[label];
-          newItem[label] = _self.getValue(property, item);
+          newItem[label] = await _self.getValue(property, current);
         }
         newData.push(newItem);
-      });
+
+        return true;
+      }, []);
 
       return newData;
     },
@@ -454,7 +457,7 @@ var script = {
       return parseData;
     },
 
-    getValue(key, item) {
+    async getValue(key, item) {
       const field = typeof key !== "object" ? key : key.field;
       let indexes = typeof field !== "string" ? [] : field.split(".");
       let value = this.defaultValue;
@@ -465,7 +468,7 @@ var script = {
       else value = this.parseValue(item[field]);
 
       if (key.hasOwnProperty("callback"))
-        value = this.getValueFromCallback(value, key.callback);
+        value = await this.getValueFromCallback(value, key.callback);
 
       return value;
     },
@@ -498,9 +501,9 @@ var script = {
       return this.parseValue(nestedItem);
     },
 
-    getValueFromCallback(item, callback) {
+    async getValueFromCallback(item, callback) {
       if (typeof callback !== "function") return this.defaultValue;
-      const value = callback(item);
+      const value = await callback(item);
       return this.parseValue(value);
     },
     parseValue(value) {
@@ -617,7 +620,11 @@ var __vue_render__ = function() {
   return _c(
     "div",
     { attrs: { id: _vm.idName }, on: { click: _vm.generate } },
-    [_vm._t("default", [_vm._v(" Download " + _vm._s(_vm.name) + " ")])],
+    [
+      _vm._t("default", function() {
+        return [_vm._v(" Download " + _vm._s(_vm.name) + " ")]
+      })
+    ],
     2
   )
 };
diff --git a/dist/vue-json-excel.umd.js b/dist/vue-json-excel.umd.js
index bd2c0dc..92d7551 100644
--- a/dist/vue-json-excel.umd.js
+++ b/dist/vue-json-excel.umd.js
@@ -275,7 +275,7 @@
 	        return;
 	      }
 
-	      let json = this.getProcessedJson(data, this.downloadFields);
+	      let json = await this.getProcessedJson(data, this.downloadFields);
 	      if (this.type === "html") {
 	        // this is mainly for testing
 	        return this.export(
@@ -416,18 +416,21 @@
 			---------------
 			Get only the data to export, if no fields are set return all the data
 			*/
-	    getProcessedJson(data, header) {
+	    async getProcessedJson(data, header) {
 	      let keys = this.getKeys(data, header);
 	      let newData = [];
 	      let _self = this;
-	      data.map(function (item, index) {
+	      await data.reduce(async function (prev, current) {
+	        await prev;
 	        let newItem = {};
 	        for (let label in keys) {
 	          let property = keys[label];
-	          newItem[label] = _self.getValue(property, item);
+	          newItem[label] = await _self.getValue(property, current);
 	        }
 	        newData.push(newItem);
-	      });
+
+	        return true;
+	      }, []);
 
 	      return newData;
 	    },
@@ -460,7 +463,7 @@
 	      return parseData;
 	    },
 
-	    getValue(key, item) {
+	    async getValue(key, item) {
 	      const field = typeof key !== "object" ? key : key.field;
 	      let indexes = typeof field !== "string" ? [] : field.split(".");
 	      let value = this.defaultValue;
@@ -471,7 +474,7 @@
 	      else value = this.parseValue(item[field]);
 
 	      if (key.hasOwnProperty("callback"))
-	        value = this.getValueFromCallback(value, key.callback);
+	        value = await this.getValueFromCallback(value, key.callback);
 
 	      return value;
 	    },
@@ -504,9 +507,9 @@
 	      return this.parseValue(nestedItem);
 	    },
 
-	    getValueFromCallback(item, callback) {
+	    async getValueFromCallback(item, callback) {
 	      if (typeof callback !== "function") return this.defaultValue;
-	      const value = callback(item);
+	      const value = await callback(item);
 	      return this.parseValue(value);
 	    },
 	    parseValue(value) {
@@ -623,7 +626,11 @@
 	  return _c(
 	    "div",
 	    { attrs: { id: _vm.idName }, on: { click: _vm.generate } },
-	    [_vm._t("default", [_vm._v(" Download " + _vm._s(_vm.name) + " ")])],
+	    [
+	      _vm._t("default", function() {
+	        return [_vm._v(" Download " + _vm._s(_vm.name) + " ")]
+	      })
+	    ],
 	    2
 	  )
 	};
diff --git a/package.json b/package.json
index 86de058..47d11bb 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "vue-json-excel",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "description": "Download your JSON as an excel or CSV file directly from the browser",
   "main": "dist/vue-json-excel.umd.js",
   "module": "dist/vue-json-excel.esm.js",
@@ -41,4 +41,4 @@
     "rollup-plugin-vue": "^4.7.2",
     "vue-template-compiler": "^2.6.10"
   }
-}
\ No newline at end of file
+}