implementation is ready

ts/index.ts

@@ -1 +1,3 @@
 import * as plugins from "./nodehash.plugins";
+
+export * from "./nodehash.sha256";

ts/nodehash.helpers.ts

@@ -0,0 +1,15 @@
+import * as plugins from "./nodehash.plugins";
+
+export let hashStreamPipeStop = (resolveFuntion) => {
+    let forEach = (chunk:Buffer,enc,cb) => {
+        resolveFuntion(chunk.toString("utf8"));
+        cb(null,chunk);
+    };
+
+    let atEnd = (cb) => {
+        cb();
+    };
+    
+    return plugins.through2(forEach,atEnd);
+};
+

ts/nodehash.plugins.ts

@@ -1,2 +1,7 @@
 import "typings-global";
-export import crypto = require("crypto");
+export import crypto = require("crypto");
+export import fs = require("fs");
+export import path = require("path");
+export import q = require("q");
+export import stream = require("stream");
+export import through2 = require("through2");

ts/nodehash.sha256.ts

@@ -0,0 +1,51 @@
+import * as plugins from "./nodehash.plugins";
+import * as helpers from "./nodehash.helpers";
+
+/**
+ * creates sha256 Hash from Stream
+ */
+export let sha256FromStream = (input) => {
+    let done = plugins.q.defer();
+    let hash = plugins.crypto.createHash('sha256');
+
+    hash["setEncoding"]("hex");
+    input
+        .pipe(hash)
+        .pipe(helpers.hashStreamPipeStop(done.resolve));
+    return done.promise;
+};
+
+/**
+ * creates sha256 Hash from File;
+ */
+export let sha256FromFile = (filePath:string) => {
+    let done = plugins.q.defer();
+    let absolutePath = plugins.path.resolve(filePath);
+    let readableStream = plugins.fs.createReadStream(absolutePath);
+    sha256FromStream(readableStream)
+        .then((resultHashString) => {
+            done.resolve(resultHashString);
+        });
+    return done.promise;
+}
+
+/**
+ * Computes sha256 Hash from String synchronously
+ */
+export let sha256FromStringSync = (stringArg) => {
+    let hash = plugins.crypto.createHash('sha256');
+    hash.update(stringArg);
+    return hash.digest("hex");
+};
+
+/**
+ * Computes sha256 Hash from String
+ */
+export let sha256FromString = (stringArg) => {
+    let done = plugins.q.defer();
+    let hash = plugins.crypto.createHash('sha256');
+    hash.update(stringArg);
+    let hashResult = hash.digest("hex");
+    done.resolve(hashResult);
+    return done.promise;
+};