Add a SHA-256 universal module

Author: jeskew

packages/crypto-sha256-universal/.gitignore

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+*.js
+*.js.map
+*.d.ts

packages/crypto-sha256-universal/__tests__/index.ts

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+import {Sha256} from '../';
+import {Sha256 as BrowserSha256} from '@aws/crypto-sha256-browser';
+import {Sha256 as NodeSha256} from '@aws/crypto-sha256-node';
+
+jest.mock('@aws/is-node', () => {
+    return { isNode: jest.fn() };
+});
+import {isNode} from '@aws/is-node';
+
+beforeEach(() => {
+    (isNode as any).mockReset();
+});
+
+describe('implementation selection', () => {
+    it('should use the node implementation in node', async () => {
+        (isNode as any).mockReturnValue(true);
+
+        const sha256 = new Sha256();
+        expect((sha256 as any).hash).toBeInstanceOf(NodeSha256);
+    });
+
+    it('should use the browser implementation elsewhere', async () => {
+        (isNode as any).mockReturnValue(false);
+
+        const sha256 = new Sha256();
+        expect((sha256 as any).hash).toBeInstanceOf(BrowserSha256);
+    });
+
+    it('should proxy method calls to underlying implementation', () => {
+        const sha256 = new Sha256();
+        const hashMock = {
+            update: jest.fn(),
+            digest: jest.fn(),
+        };
+        (sha256 as any).hash = hashMock;
+
+        sha256.update('foo', 'utf8');
+        expect(hashMock.update.mock.calls.length).toBe(1);
+        expect(hashMock.update.mock.calls[0]).toEqual(['foo', 'utf8']);
+
+        const promise = sha256.digest();
+        expect(hashMock.digest.mock.calls.length).toBe(1);
+    });
+});

packages/crypto-sha256-universal/index.ts

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+import {isNode} from '@aws/is-node';
+import {Sha256 as BrowserSha256} from '@aws/crypto-sha256-browser';
+import {Sha256 as NodeSha256} from '@aws/crypto-sha256-node';
+import {Hash, SourceData} from '@aws/types';
+
+export class Sha256 implements Hash {
+    private readonly hash: Hash;
+
+    constructor(secret?: SourceData) {
+        if (isNode()) {
+            this.hash = new NodeSha256(secret);
+        } else {
+            this.hash = new BrowserSha256(secret);
+        }
+    }
+
+    update(data: SourceData, encoding?: 'utf8' | 'ascii' | 'latin1'): void {
+        this.hash.update(data, encoding);
+    }
+
+    digest(): Promise<Uint8Array> {
+        return this.hash.digest();
+    }
+}

packages/crypto-sha256-universal/package.json

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+{
+  "name": "@aws/crypto-sha256-universal",
+  "private": true,
+  "version": "0.0.1",
+  "scripts": {
+    "prepublishOnly": "tsc",
+    "pretest": "tsc",
+    "test": "jest"
+  },
+  "author": "[email protected]",
+  "license": "UNLICENSED",
+  "dependencies": {
+    "@aws/crypto-sha256-browser": "^0.0.1",
+    "@aws/crypto-sha256-node": "^0.0.1",
+    "@aws/types": "^0.0.1",
+    "@aws/is-node": "^0.0.1"
+  },
+  "devDependencies": {
+    "@types/jest": "^19.2.2",
+    "@types/node": "^7.0.12",
+    "@types/text-encoding": "0.0.30",
+    "jest": "^19.0.2",
+    "typescript": "^2.3"
+  }
+}

packages/crypto-sha256-universal/tsconfig.json

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+{
+  "compilerOptions": {
+     "target": "es5",
+     "module": "commonjs",
+     "lib": [
+       "DOM",
+       "ES5",
+       "ScriptHost",
+       "ES2015.Promise"
+     ],
+     "declaration": true,
+     "sourceMap": true,
+     "strict": true
+  }
+}