diff --git a/src/payments/embed.js b/src/payments/embed.js
index 0e2a0ae..800c8de 100644
--- a/src/payments/embed.js
+++ b/src/payments/embed.js
@@ -1,14 +1,14 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
+const networks_1 = require("../networks");
 const bscript = require("../script");
 const lazy = require("./lazy");
-const networks_1 = require("../networks");
 const typef = require('typeforce');
 const OPS = bscript.OPS;
 function stacksEqual(a, b) {
     if (a.length !== b.length)
         return false;
-    return a.every(function (x, i) {
+    return a.every((x, i) => {
         return x.equals(b[i]);
     });
 }
@@ -24,12 +24,12 @@ function p2data(a, opts) {
     }, a);
     const network = a.network || networks_1.bitcoin;
     const o = { network };
-    lazy.prop(o, 'output', function () {
+    lazy.prop(o, 'output', () => {
         if (!a.data)
             return;
         return bscript.compile([OPS.OP_RETURN].concat(a.data));
     });
-    lazy.prop(o, 'data', function () {
+    lazy.prop(o, 'data', () => {
         if (!a.output)
             return;
         return bscript.decompile(a.output).slice(1);
diff --git a/ts_src/payments/embed.ts b/ts_src/payments/embed.ts
index d7a2b0f..38a8162 100644
--- a/ts_src/payments/embed.ts
+++ b/ts_src/payments/embed.ts
@@ -1,14 +1,15 @@
-import { Payment, PaymentOpts } from './index';
+import { bitcoin as BITCOIN_NETWORK } from '../networks';
 import * as bscript from '../script';
+import { Payment, PaymentOpts, Stack } from './index';
 import * as lazy from './lazy';
-import { bitcoin as BITCOIN_NETWORK } from '../networks';
+
 const typef = require('typeforce');
 const OPS = bscript.OPS;
 
-function stacksEqual(a: Array<Buffer>, b: Array<Buffer>): boolean {
+function stacksEqual(a: Buffer[], b: Buffer[]): boolean {
   if (a.length !== b.length) return false;
 
-  return a.every(function(x, i) {
+  return a.every((x, i) => {
     return x.equals(b[i]);
   });
 }
@@ -28,15 +29,13 @@ export function p2data(a: Payment, opts?: PaymentOpts): Payment {
   );
 
   const network = a.network || BITCOIN_NETWORK;
-  const o = <Payment>{ network };
+  const o = { network } as Payment;
 
-  lazy.prop(o, 'output', function() {
+  lazy.prop(o, 'output', () => {
     if (!a.data) return;
-    return bscript.compile(
-      (<Array<Buffer | number>>[OPS.OP_RETURN]).concat(a.data),
-    );
+    return bscript.compile(([OPS.OP_RETURN] as Stack).concat(a.data));
   });
-  lazy.prop(o, 'data', function() {
+  lazy.prop(o, 'data', () => {
     if (!a.output) return;
     return bscript.decompile(a.output)!.slice(1);
   });
@@ -50,7 +49,7 @@ export function p2data(a: Payment, opts?: PaymentOpts): Payment {
       if (!chunks!.slice(1).every(typef.Buffer))
         throw new TypeError('Output is invalid');
 
-      if (a.data && !stacksEqual(a.data, <Array<Buffer>>o.data))
+      if (a.data && !stacksEqual(a.data, o.data as Buffer[]))
         throw new TypeError('Data mismatch');
     }
   }
diff --git a/ts_src/payments/index.ts b/ts_src/payments/index.ts
index 6727eeb..4f6eb75 100644
--- a/ts_src/payments/index.ts
+++ b/ts_src/payments/index.ts
@@ -10,18 +10,18 @@ import { p2wsh } from './p2wsh';
 export interface Payment {
   network?: Network;
   output?: Buffer;
-  data?: Array<Buffer>;
+  data?: Buffer[];
   m?: number;
   n?: number;
-  pubkeys?: Array<Buffer>;
+  pubkeys?: Buffer[];
   input?: Buffer;
-  signatures?: Array<Buffer>;
+  signatures?: Buffer[];
   pubkey?: Buffer;
   signature?: Buffer;
   address?: string;
   hash?: Buffer;
   redeem?: Payment;
-  witness?: Array<Buffer>;
+  witness?: Buffer[];
 }
 
 export interface PaymentOpts {
@@ -29,6 +29,9 @@ export interface PaymentOpts {
   allowIncomplete?: boolean;
 }
 
+export type StackElement = Buffer | number;
+export type Stack = StackElement[];
+
 export { embed, p2ms, p2pk, p2pkh, p2sh, p2wpkh, p2wsh };
 
 // TODO
diff --git a/types/payments/index.d.ts b/types/payments/index.d.ts
index 5afc847..3009bef 100644
--- a/types/payments/index.d.ts
+++ b/types/payments/index.d.ts
@@ -10,21 +10,23 @@ import { p2wsh } from './p2wsh';
 export interface Payment {
     network?: Network;
     output?: Buffer;
-    data?: Array<Buffer>;
+    data?: Buffer[];
     m?: number;
     n?: number;
-    pubkeys?: Array<Buffer>;
+    pubkeys?: Buffer[];
     input?: Buffer;
-    signatures?: Array<Buffer>;
+    signatures?: Buffer[];
     pubkey?: Buffer;
     signature?: Buffer;
     address?: string;
     hash?: Buffer;
     redeem?: Payment;
-    witness?: Array<Buffer>;
+    witness?: Buffer[];
 }
 export interface PaymentOpts {
     validate?: boolean;
     allowIncomplete?: boolean;
 }
+export declare type StackElement = Buffer | number;
+export declare type Stack = StackElement[];
 export { embed, p2ms, p2pk, p2pkh, p2sh, p2wpkh, p2wsh };