refactor: move pickContext to its own module

libs/fetcher.client.js

@@ -10,12 +10,14 @@
  * @module Fetcher
  */
 var REST = require('./util/http.client');
+var defaultConstructGetUri = require('./util/defaultConstructGetUri');
+var forEach = require('./util/forEach');
+var pickContext = require('./util/pickContext');
+
 var DEFAULT_PATH = '/api';
 var DEFAULT_TIMEOUT = 3000;
 var MAX_URI_LEN = 2048;
 var OP_READ = 'read';
-var defaultConstructGetUri = require('./util/defaultConstructGetUri');
-var forEach = require('./util/forEach');
 
 function parseResponse(response) {
     if (response && response.responseText) {
@@ -28,43 +30,6 @@ function parseResponse(response) {
     return null;
 }
 
-/**
- * Pick keys from the context object
- * @method pickContext
- * @param {Object} context - context object
- * @param {Function|Array|String} picker - key, array of keys or
- * function that return keys to be extracted from context.
- * @param {String} method - method name, GET or POST
- */
-function pickContext(context, picker, method) {
-    if (!picker || !picker[method]) {
-        return context;
-    }
-
-    var p = picker[method];
-    var result = {};
-
-    if (typeof p === 'string') {
-        result[p] = context[p];
-    } else if (Array.isArray(p)) {
-        p.forEach(function (key) {
-            result[key] = context[key];
-        });
-    } else if (typeof p === 'function') {
-        forEach(context, function (value, key) {
-            if (p(value, key, context)) {
-                result[key] = context[key];
-            }
-        });
-    } else {
-        throw new TypeError(
-            'picker must be an string, an array, or a function.'
-        );
-    }
-
-    return result;
-}
-
 /**
  * A RequestClient instance represents a single fetcher request.
  * The constructor requires `operation` (CRUD) and `resource`.

libs/util/pickContext.js

@@ -0,0 +1,40 @@
+var forEach = require('./forEach');
+
+/**
+ * Pick keys from the context object
+ * @method pickContext
+ * @param {Object} context - context object
+ * @param {Function|Array|String} picker - key, array of keys or
+ * function that return keys to be extracted from context.
+ * @param {String} method - method name, GET or POST
+ */
+function pickContext(context, picker, method) {
+    if (!picker || !picker[method]) {
+        return context;
+    }
+
+    var p = picker[method];
+    var result = {};
+
+    if (typeof p === 'string') {
+        result[p] = context[p];
+    } else if (Array.isArray(p)) {
+        p.forEach(function (key) {
+            result[key] = context[key];
+        });
+    } else if (typeof p === 'function') {
+        forEach(context, function (value, key) {
+            if (p(value, key, context)) {
+                result[key] = context[key];
+            }
+        });
+    } else {
+        throw new TypeError(
+            'picker must be an string, an array, or a function.'
+        );
+    }
+
+    return result;
+}
+
+module.exports = pickContext;