diff --git a/src/common/parser/Params.test.ts b/src/common/parser/Params.test.ts
index 564b0d565..4b45ba3f8 100644
--- a/src/common/parser/Params.test.ts
+++ b/src/common/parser/Params.test.ts
@@ -113,6 +113,10 @@ describe('Params', () => {
     data = [38, [2, 50, 100, 150], 5, [], 6];
     assert.deepEqual(Params.fromArray(data).toArray(), [38, [2, 50, 100, 150], 5, 6]);
   });
+  it('clone', () => {
+    const params = Params.fromArray([38, [2, 50, 100, 150], 5, [], 6, 1, [2, 3], 12345, [-1]]);
+    assert.deepEqual(params.clone(), params);
+  });
   it('hasSubParams / getSubParams', () => {
     const params = Params.fromArray([38, [2, 50, 100, 150], 5, [], 6]);
     assert.equal(params.hasSubParams(0), true);
diff --git a/src/common/parser/Params.ts b/src/common/parser/Params.ts
index bc1880ed8..74cd5a798 100644
--- a/src/common/parser/Params.ts
+++ b/src/common/parser/Params.ts
@@ -2,36 +2,7 @@
  * Copyright (c) 2019 The xterm.js authors. All rights reserved.
  * @license MIT
  */
-
-// TODO: move to Types
-interface IParamsConstructor {
-  new(maxLength: number, maxSubParamsLength: number): IParams;
-  fromArray(values: (number | number[])[]): IParams;
-}
-
-interface IParams {
-  /** from ctor */
-  maxLength: number;
-  maxSubParamsLength: number;
-
-  /** param values and its length */
-  params: Int16Array;
-  length: number;
-
-  /** sub params and its length */
-  subParams: Int16Array;
-  subParamsLength: number;
-
-  /** methods */
-  clone(): IParams;
-  toArray(): (number | number[])[];
-  reset(): void;
-  addParam(value: number): void;
-  addSubParam(value: number): void;
-  hasSubParams(idx: number): boolean;
-  getSubParams(idx: number): Int16Array | null;
-  getSubParamsAll(): {[idx: number]: Int16Array};
-}
+import { IParams } from 'common/parser/Types';
 
 /**
  * Params storage class.
diff --git a/src/common/parser/Types.d.ts b/src/common/parser/Types.d.ts
index 47ec98e15..ffd175d66 100644
--- a/src/common/parser/Types.d.ts
+++ b/src/common/parser/Types.d.ts
@@ -6,6 +6,40 @@
 import { IDisposable } from 'common/Types';
 import { ParserState } from 'common/parser/Constants';
 
+/**
+ * Params types.
+ */
+export interface IParamsConstructor {
+  new(maxLength: number, maxSubParamsLength: number): IParams;
+
+  /** create params object from array like [1, [2, 3]] */
+  fromArray(values: (number | number[])[]): IParams;
+}
+
+export interface IParams {
+  /** from ctor */
+  maxLength: number;
+  maxSubParamsLength: number;
+
+  /** param values and its length */
+  params: Int16Array;
+  length: number;
+
+  /** sub params and its length */
+  subParams: Int16Array;
+  subParamsLength: number;
+
+  /** methods */
+  clone(): IParams;
+  toArray(): (number | number[])[];
+  reset(): void;
+  addParam(value: number): void;
+  addSubParam(value: number): void;
+  hasSubParams(idx: number): boolean;
+  getSubParams(idx: number): Int16Array | null;
+  getSubParamsAll(): {[idx: number]: Int16Array};
+}
+
 /**
  * Internal state of EscapeSequenceParser.
  * Used as argument of the error handler to allow