loadUrl enhancements (#134)

`loadUrl` enhancements

- Make `options` parameter optional
- Allow partial overriding of instance options when calling `loadUrl` directly
- Make `requestOptions` optional
- Document `loadUrl` usage and provide examples

tests/lib/parse-options.js

@@ -0,0 +1,49 @@
+var tape = require("tape")
+
+var parseOptions = require("../../lib/parse-options.js")
+tape("test parse initalization options function", function(t) {
+  t.test("- default options", function(t) {
+    var pjax = {}
+    pjax.options = parseOptions({})
+
+    t.equal(pjax.options.elements, "a[href], form[action]")
+    t.equal(pjax.options.selectors.length, 2, "selectors length")
+    t.equal(pjax.options.selectors[0], "title")
+    t.equal(pjax.options.selectors[1], ".js-Pjax")
+
+    t.equal(typeof pjax.options.switches, "object")
+    t.equal(Object.keys(pjax.options.switches).length, 2)// head and body
+
+    t.equal(typeof pjax.options.switchesOptions, "object")
+    t.equal(Object.keys(pjax.options.switchesOptions).length, 0)
+
+    t.equal(pjax.options.history, true)
+    t.equal(typeof pjax.options.analytics, "function")
+    t.equal(pjax.options.scrollTo, 0)
+    t.equal(pjax.options.scrollRestoration, true)
+    t.equal(pjax.options.cacheBust, true)
+    t.equal(pjax.options.debug, false)
+    t.equal(pjax.options.currentUrlFullReload, false)
+    t.end()
+  })
+
+  // verify analytics always ends up as a function even when passed not a function
+  t.test("- analytics is a function", function(t) {
+    var pjax = {}
+    pjax.options = parseOptions({analytics: "some string"})
+
+    t.deepEqual(typeof pjax.options.analytics, "function")
+    t.end()
+  })
+
+  // verify that the value false for scrollTo is not squashed
+  t.test("- scrollTo remains false", function(t) {
+    var pjax = {}
+    pjax.options = parseOptions({scrollTo: false})
+
+    t.deepEqual(pjax.options.scrollTo, false)
+    t.end()
+  })
+
+  t.end()
+})