Refactor of codes in node.js

1) Add async method: `binarySearch` and `btreeSearch`.
2) Refactor of tests by putting them into `tests` folder.
3) Create several new tests in details.
4) Remove useless and reformat codes to be clear.
5) Remove useless snapshots, because they can be recreated when you run `npm run test`.

binding/nodejs/tests/utils/asyncFor.js

@@ -0,0 +1,23 @@
+/**
+ * Async For
+ * @param {Array} groupArray 
+ * @param {Function} exeCallBack 
+ * @param {Function} finalCallBack 
+ */
+function asyncFor(groupArray, exeCallBack, finalCallBack) {
+
+    let i = 0;
+
+    function _innerAsyncLoop() {
+        if (i < groupArray.length) {
+            exeCallBack(groupArray[i++], _innerAsyncLoop);
+        }
+        else {
+            finalCallBack();
+        }
+    }
+
+    _innerAsyncLoop();
+}
+
+module.exports = asyncFor;

binding/nodejs/tests/utils/fetchMainVersion.js

@@ -0,0 +1,9 @@
+let node_ver = process.version
+// Because nodejs's version is something like `v8.11.3`. So we should ignore `v` first
+node_ver = node_ver.substr(1);
+// Splitted by `.`
+node_ver = node_ver.split('.');
+// Take the main version number
+node_ver = parseInt(node_ver[0]);
+
+module.exports = node_ver;

binding/nodejs/tests/utils/testData.js

@@ -0,0 +1,16 @@
+module.exports = [
+    '0.0.0.0',
+    '10.10.10.10',
+    '210.109.255.230',
+    '192.168.0.1',
+    '255.255.255.255',
+    '77.49.66.88',
+    '210.248.255.231',
+    '35.193.251.120',
+    '197.84.60.202',
+    '183.196.233.159',
+    '20.108.91.101',
+    '120.196.148.137',
+    '249.255.250.200',
+    '112.65.1.130'
+]