diff --git a/types/fast-json-patch/fast-json-patch-tests.ts b/types/fast-json-patch/fast-json-patch-tests.ts
index 15ac0d57f1..10f8c376cb 100644
--- a/types/fast-json-patch/fast-json-patch-tests.ts
+++ b/types/fast-json-patch/fast-json-patch-tests.ts
@@ -1,41 +1,39 @@
-import * as jsonpatch from 'fast-json-patch'
+import * as jsonpatch from 'fast-json-patch';
 
-var myobj:{
-    firstName:string,
-    contactDetails: {
-        phoneNumbers:string[]
-    }
-} = { firstName:"Albert", contactDetails: { phoneNumbers: [ ] } };
-var patches = [
-   {op:"replace", path:"/firstName", value:"Joachim" },
-   {op:"add", path:"/lastName", value:"Wester" },
-   {op:"add", path:"/contactDetails/phoneNumbers/0", value:{ number:"555-123" }  }
-   ];
-jsonpatch.apply( myobj, patches );
+var myobj: {
+  firstName: string,
+  contactDetails: {
+    phoneNumbers: string[]
+  }
+} = { firstName: "Albert", contactDetails: { phoneNumbers: [] } };
+var patches: jsonpatch.Patch[] = [
+  { op: "replace", path: "/firstName", value: "Joachim" },
+  { op: "add", path: "/lastName", value: "Wester" },
+  { op: "add", path: "/contactDetails/phoneNumbers/0", value: { number: "555-123" } }
+];
+jsonpatch.apply(myobj, patches);
 
-var myobj2 = { firstName:"Joachim", lastName:"Wester", contactDetails: { phoneNumbers: [ { number:"555-123" }] } };
-var observer = jsonpatch.observe( myobj2 );
+var myobj2 = { firstName: "Joachim", lastName: "Wester", contactDetails: { phoneNumbers: [{ number: "555-123" }] } };
+var observer = jsonpatch.observe(myobj2);
 myobj2.firstName = "Albert";
 myobj2.contactDetails.phoneNumbers[0].number = "123";
-myobj2.contactDetails.phoneNumbers.push({number:"456"});
+myobj2.contactDetails.phoneNumbers.push({ number: "456" });
 var patches2 = jsonpatch.generate(observer);
 
-var objA = {user: {firstName: "Albert", lastName: "Einstein"}};
-var objB = {user: {firstName: "Albert", lastName: "Collins"}};
+var objA = { user: { firstName: "Albert", lastName: "Einstein" } };
+var objB = { user: { firstName: "Albert", lastName: "Collins" } };
 var diff = jsonpatch.compare(objA, objB);
 
-var obj = {user: {firstName: "Albert"}};
-var patches3 = [{op: "replace", path: "/user/firstName", value: "Albert"}, {op: "replace", path: "/user/lastName", value: "Einstein"}];
+var obj = { user: { firstName: "Albert" } };
+var patches3 = [{ op: "replace", path: "/user/firstName", value: "Albert" }, { op: "replace", path: "/user/lastName", value: "Einstein" }];
 var errors = jsonpatch.validate(patches, obj);
-if (errors.length == 0) {
- //there are no errors!
-}
-else {
-  for (var i=0; i < errors.length; i++) {
+if (errors.length === 0) {
+  //there are no errors!
+} else {
+  for (var i = 0; i < errors.length; i++) {
     if (!errors[i]) {
       console.log("Valid patch at index", i, patches[i]);
-    }
-    else {
+    } else {
       console.error("Invalid patch at index", i, errors[i], patches[i]);
     }
   }
diff --git a/types/fast-json-patch/index.d.ts b/types/fast-json-patch/index.d.ts
index 9a4496b00c..02c8c0e25e 100644
--- a/types/fast-json-patch/index.d.ts
+++ b/types/fast-json-patch/index.d.ts
@@ -1,67 +1,104 @@
-// Type definitions for JSON-Patch v1.0.0
+// Type definitions for JSON-Patch v1.1.8
 // Project: https://github.com/Starcounter-Jack/JSON-Patch/releases
 // Definitions by: Francis OBrien <https://github.com/itsFrank>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 declare namespace fastjsonpatch {
-    
 
-    interface JsonPatch {
-        /**
-         * Applies an array of patch instructions to an object
-         */
-        apply(object:any, patches:Patch[], validate?:boolean):boolean
-        
-        /**
-         * Observes changes made to an object, which can then be retieved using generate
-         */
-        observe<T>(object:T, callback?:()=>void):Observer<T>
-        
-        /**
-         * Detach an observer from an object
-         */
-        unobserve<T>(object:T, observer:Observer<T>):void
+    type Patch = AddPatch | RemovePatch | ReplacePatch | MovePatch | CopyPatch | TestPatch;
 
-        /**
-         * Generate an array of patches from an observer
-         */
-        generate<T>(observer:Observer<T>):Patch[]
-
-        /**
-         * Create an array of patches from the differences in two objects
-         */
-        compare(object1:any, object2:any):Patch[]
-
-        /**
-         * Ensure a set of patch instructions is valid
-         */
-        validate(patches:Patch[], tree?:any):JsonPatchError[]
+    interface PatchBase {
+        path: string;
     }
-    
+
+    interface AddPatch extends PatchBase {
+        op: 'add';
+        value: any;
+    }
+
+    interface RemovePatch extends PatchBase {
+        op: 'remove';
+    }
+
+    interface ReplacePatch extends PatchBase {
+        op: 'replace';
+        value: any;
+    }
+
+    interface MovePatch extends PatchBase {
+        op: 'move';
+        from: string;
+    }
+
+    interface CopyPatch extends PatchBase {
+        op: 'copy';
+        from: string;
+    }
+
+    interface TestPatch extends PatchBase {
+        op: 'test';
+        value: any;
+    }
+
     interface Observer<T> {
-        object:T
-        patches:Patch[]
-        unobserve():void
+        object: T
+        patches: Patch[]
+        unobserve(): void
     }
 
-    interface Patch {
-        op:string
-        path:string
-        value?:any
-        from?:string
-    }
+    type JsonPatchErrorName = 'SEQUENCE_NOT_AN_ARRAY' |
+        'OPERATION_NOT_AN_OBJECT' |
+        'OPERATION_OP_INVALID' |
+        'OPERATION_PATH_INVALID' |
+        'OPERATION_FROM_REQUIRED' |
+        'OPERATION_VALUE_REQUIRED' |
+        'OPERATION_VALUE_CANNOT_CONTAIN_UNDEFINED' |
+        'OPERATION_PATH_CANNOT_ADD' |
+        'OPERATION_PATH_UNRESOLVABLE' |
+        'OPERATION_FROM_UNRESOLVABLE' |
+        'OPERATION_PATH_ILLEGAL_ARRAY_INDEX' |
+        'OPERATION_VALUE_OUT_OF_BOUNDS';
 
     interface JsonPatchError {
-        name:string
-        message:string
-        index:number
-        operation:any
-        tree:any
+        name: JsonPatchErrorName
+        message: string
+        index: number
+        operation: any
+        tree: any
     }
+
+    /**
+     * Applies an array of patch instructions to an object
+     */
+    function apply(object: any, patches: Patch[], validate?: boolean): any[]
+
+    /**
+     * Observes changes made to an object, which can then be retieved using generate
+     */
+    function observe<T>(object: T, callback?: () => void): Observer<T>
+
+    /**
+     * Detach an observer from an object
+     */
+    function unobserve<T>(object: T, observer: Observer<T>): void
+
+    /**
+     * Generate an array of patches from an observer
+     */
+    function generate<T>(observer: Observer<T>): Patch[]
+
+    /**
+     * Create an array of patches from the differences in two objects
+     */
+    function compare(object1: any, object2: any): Patch[]
+
+    /**
+     * Ensure a set of patch instructions is valid
+     */
+    function validate(patches: Patch[], tree?: any): JsonPatchError[]
+
 }
 
-declare  var jsonpatch: fastjsonpatch.JsonPatch;
-
 declare module "fast-json-patch" {
-    export = jsonpatch
+    export = fastjsonpatch
 }
\ No newline at end of file