Remove duplicated code from hash functions

Author: alcuadrado

packages/ethereum-cryptography/src/hash-utils.ts

@@ -0,0 +1,11 @@
+import { Hash } from "crypto";
+
+export function createHashFunction(
+  hashConstructor: () => Hash
+): (msg: Buffer) => Buffer {
+  return msg => {
+    const hash = hashConstructor();
+    hash.update(msg);
+    return Buffer.from(hash.digest());
+  };
+}

packages/ethereum-cryptography/src/pure/ripemd160.ts

@@ -1,8 +1,5 @@
 const { ripemd160: Ripemd160 } = require("hash.js/lib/hash/ripemd");
 
-export function ripemd160(msg: Buffer): Buffer {
-  const hash = new Ripemd160();
-  hash.update(msg);
+import { createHashFunction } from "../hash-utils";
 
-  return Buffer.from(hash.digest());
-}
+export const ripemd160 = createHashFunction(() => new Ripemd160());

packages/ethereum-cryptography/src/pure/sha256.ts

@@ -1,8 +1,5 @@
 const Sha256Hash = require("hash.js/lib/hash/sha/256");
 
-export function sha256(msg: Buffer): Buffer {
-  const hash = new Sha256Hash();
-  hash.update(msg);
+import { createHashFunction } from "../hash-utils";
 
-  return Buffer.from(hash.digest());
-}
+export const sha256 = createHashFunction(() => new Sha256Hash());

packages/ethereum-cryptography/src/ripemd160.ts

@@ -1,7 +1,7 @@
 import crypto from "crypto";
 
-export function ripemd160(msg: Buffer): Buffer {
-  const hash = crypto.createHash("ripemd160");
-  hash.update(msg);
-  return Buffer.from(hash.digest());
-}
+import { createHashFunction } from "./hash-utils";
+
+export const ripemd160 = createHashFunction(() =>
+  crypto.createHash("ripemd160")
+);

packages/ethereum-cryptography/src/sha256.ts

@@ -1,7 +1,5 @@
 import crypto from "crypto";
 
-export function sha256(msg: Buffer): Buffer {
-  const hash = crypto.createHash("sha256");
-  hash.update(msg);
-  return Buffer.from(hash.digest());
-}
+import { createHashFunction } from "./hash-utils";
+
+export const sha256 = createHashFunction(() => crypto.createHash("sha256"));