{address,u8a}Eq functions (#606)

* {addres,u8a}Eq functions

* Remove mnemonicToSeed

packages/util/src/u8a/eq.spec.ts

@@ -0,0 +1,43 @@
+// Copyright 2017-2020 @polkadot/util authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { u8aEq } from '.';
+
+describe('u8aEq', (): void => {
+  it('returns false when the lengths do not match', (): void => {
+    expect(
+      u8aEq(
+        new Uint8Array([1, 2, 3]),
+        new Uint8Array([1, 2])
+      )
+    ).toEqual(false);
+  });
+
+  it('returns false when the contents do not match', (): void => {
+    expect(
+      u8aEq(
+        new Uint8Array([1, 2, 3]),
+        new Uint8Array([1, 2, 4])
+      )
+    ).toEqual(false);
+  });
+
+  it('returns true when the contents do match', (): void => {
+    expect(
+      u8aEq(
+        new Uint8Array([1, 2, 3]),
+        new Uint8Array([1, 2, 3])
+      )
+    ).toEqual(true);
+  });
+
+  it('returns true with equalvalent hex & Uint8array', (): void => {
+    expect(
+      u8aEq(
+        '0x010203',
+        new Uint8Array([1, 2, 3])
+      )
+    ).toEqual(true);
+  });
+});

packages/util/src/u8a/eq.ts

@@ -0,0 +1,37 @@
+// Copyright 2017-2020 @polkadot/util authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import u8aToU8a from './toU8a';
+
+function equals (a: Uint8Array, b: Uint8Array): boolean {
+  if (a.length !== b.length) {
+    return false;
+  }
+
+  for (let i = 0; i < a.length; i++) {
+    if (a[i] !== b[i]) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+/**
+ * @name u8aEq
+ * @summary Compares two Uint8Arrays.
+ * @description
+ * For `UInt8Array` (or hex string) input values true if there is a match.
+ * @example
+ * <BR>
+ *
+ * ```javascript
+ * import { u8aEq } from '@polkadot/util';
+ *
+ * u8aEq(new Uint8Array([0x68, 0x65]), new Uint8Array([0x68, 0x65])); // true
+ * ```
+ */
+export default function u8aEq (a: Uint8Array | string, b: Uint8Array | string): boolean {
+  return equals(u8aToU8a(a), u8aToU8a(b));
+}

packages/util/src/u8a/index.ts

@@ -7,6 +7,7 @@
  */
 
 export { default as u8aConcat } from './concat';
+export { default as u8aEq } from './eq';
 export { default as u8aFixLength } from './fixLength';
 export { default as u8aSorted } from './sorted';
 export { default as u8aToBn } from './toBn';

packages/util/src/u8a/toHex.ts

@@ -2,7 +2,11 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-const ALPHABET = '0123456789abcdef';
+const ALPHABET = new Array(256) as string[];
+
+for (let n = 0; n < 256; ++n) {
+  ALPHABET[n] = n.toString(16).padStart(2, '0');
+}
 
 /**
  * @name u8aToHex
@@ -35,10 +39,11 @@ export default function u8aToHex (value?: Uint8Array | null, bitLength = -1, isP
     return `${u8aToHex(value.subarray(0, halfLength), -1, isPrefixed)}…${u8aToHex(value.subarray(value.length - halfLength), -1, false)}`;
   }
 
-  // based on comments in https://stackoverflow.com/questions/40031688/javascript-arraybuffer-to-hex and
-  // implementation in http://jsben.ch/Vjx2V - optimisation here suggests that a forEach loop is faster
-  // than reduce as well (clocking at in 90% of the reduce speed with tweaking in the playpen above)
-  return value.reduce((result, value): string => {
-    return result + ALPHABET[value >> 4] + ALPHABET[value & 15];
-  }, prefix);
+  const result = new Array(value.length) as string[];
+
+  for (let i = 0; i < value.length; i++) {
+    result[i] = ALPHABET[value[i]];
+  }
+
+  return prefix + result.join('');
 }