diff --git a/packages/easy/src/types/Parser.ts b/packages/easy/src/types/Parser.ts
index 70cd18e3a..7235887f2 100644
--- a/packages/easy/src/types/Parser.ts
+++ b/packages/easy/src/types/Parser.ts
@@ -6,26 +6,26 @@ import { toArray } from './Array';
 
 export class Parser<T, V> {
   if = {
-    equals: (pred?: Predicate<T>): this => this.evaluate(isTrue, pred),
-    empty: <U>(pred?: Get<U, T>): this => this.evaluate(isEmpty, pred),
-    defined: <U>(pred?: Get<U, T>): this => this.evaluate(isDefined, pred),
-    valid: <U>(pred?: Get<U, T>): this => this.evaluate(isValid, pred),
-    in: (...items: T[]): this => this.evaluate(() => isIn(this.value, toArray(...items))),
+    equals: (pred?: Predicate<T>): Parser<T, V> => this.evaluate(isTrue, pred),
+    empty: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluate(isEmpty, pred),
+    defined: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluate(isDefined, pred),
+    valid: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluate(isValid, pred),
+    in: (...items: T[]): Parser<T, V> => this.evaluate(() => isIn(this.value, toArray(...items))),
     is: {
-      object: <U>(pred?: Get<U, T>): this => this.evaluate(isObject, pred),
-      string: <U>(pred?: Get<U, T>): this => this.evaluate(isString, pred),
-      instance: <U>(c: Constructor<U>, pred?: Get<U, T>): this => this.evaluate(() => this.value instanceof c, pred),
+      object: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluate(isObject, pred),
+      string: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluate(isString, pred),
+      instance: <U>(c: Constructor<U>, pred?: Get<U, T>): Parser<T, V> => this.evaluate(() => this.value instanceof c, pred),
     },
     not: {
-      empty: <U>(pred?: Get<U, T>): this => this.evaluateNot(isEmpty, pred),
-      defined: <U>(pred?: Get<U, T>): this => this.evaluateNot(isDefined, pred),
-      valid: <U>(pred?: Get<U, T>): this => this.evaluateNot(isValid, pred),
-      isObject: <U>(pred?: Get<U, T>): this => this.evaluateNot(isObject, pred),
-      in: (...items: T[]): this => this.evaluate(() => !isIn(this.value, toArray(...items))),
+      empty: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isEmpty, pred),
+      defined: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isDefined, pred),
+      valid: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isValid, pred),
+      isObject: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isObject, pred),
+      in: (...items: T[]): Parser<T, V> => this.evaluate(() => !isIn(this.value, toArray(...items))),
       is: {
-        object: <U>(pred?: Get<U, T>): this => this.evaluateNot(isObject, pred),
-        string: <U>(pred?: Get<U, T>): this => this.evaluateNot(isString, pred),
-        instance: <U>(c: Constructor<U>, pred?: Get<U, T>): this => this.evaluate(() => !(this.value instanceof c), pred),
+        object: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isObject, pred),
+        string: <U>(pred?: Get<U, T>): Parser<T, V> => this.evaluateNot(isString, pred),
+        instance: <U>(c: Constructor<U>, pred?: Get<U, T>): Parser<T, V> => this.evaluate(() => !(this.value instanceof c), pred),
       },
     },
   };
@@ -35,11 +35,11 @@ export class Parser<T, V> {
     protected valid = true
   ) {}
 
-  protected evaluate<U>(meta: Get<boolean>, pred?: Get<U, T>): this {
+  protected evaluate<U>(meta: Get<boolean>, pred?: Get<U, T>): Parser<T, V> {
     return on(this, t => (t.valid = ofGet(meta, pred ? ofGet(pred, this.value) : this.value)));
   }
 
-  protected evaluateNot<U>(meta: Get<boolean>, pred?: Get<U, T>): this {
+  protected evaluateNot<U>(meta: Get<boolean>, pred?: Get<U, T>): Parser<T, V> {
     return on(this, t => (t.valid = !ofGet(meta, pred ? ofGet(pred, this.value) : this.value)));
   }
 }