Clarify pathname docs, follow spec with fragments (#2448)

* Clarify pathname docs, follow spec with fragments

- Valid URLs must not contain a `#` within its fragment.
  https://github.com/MithrilJS/mithril.js/issues/2445
- Our docs were a little confusing and misleading - `m.pathname` isn't
  aware of URLs, just path names.
- Removed the relevant extension to `m.parseQueryString` required to
  support the hash parsing extension. Now we just shave it off and
  ignore it.
- Fix support for arbitrary prefixes, so prefixes like `?#` are
  handled correctly.
- Add a bunch of tests to cover various areas of confusion and unusual
  edge cases.

* Update with PR [skip ci]

docs/change-log.md

@@ -43,6 +43,8 @@
 - request: set `Content-Type: application/json; charset=utf-8` for all XHR methods by default, provided they have a body that's `!= null` ([#2361](https://github.com/MithrilJS/mithril.js/pull/2361), [#2421](https://github.com/MithrilJS/mithril.js/pull/2421))
     - This can cause CORS issues when issuing `GET` with bodies, but you can address them through configuring CORS appropriately.
     - Previously, it was only set for all non-`GET` methods and only when `useBody: true` was passed (the default), and it was always set for them. Now it's automatically omitted when no body is present, so the hole is slightly broadened.
+- route: query parameters in hash strings are no longer supported ([#2448](https://github.com/MithrilJS/mithril.js/pull/2448) [@isiahmeadows](https://github.com/isiahmeadows))
+    - It's technically invalid in hashes, so I'd rather push people to keep in line with spec.
 
 #### News
 
@@ -96,6 +98,7 @@
 - request: autoredraw support fixed for `async`/`await` in Chrome ([#2428](https://github.com/MithrilJS/mithril.js/pull/2428) [@isiahmeadows](https://github.com/isiahmeadows))
 - render: fix when attrs change with `onbeforeupdate` returning false, then remaining the same on next redraw ([#2447](https://github.com/MithrilJS/mithril.js/pull/2447) [@isiahmeadows](https://github.com/isiahmeadows))
 - render: fix internal error when `onbeforeupdate` returns false and then true with new child tree ([#2447](https://github.com/MithrilJS/mithril.js/pull/2447) [@isiahmeadows](https://github.com/isiahmeadows))
+- route: arbitrary prefixes are properly supported now, including odd prefixes like `?#` and invalid prefixes like `#foo#bar` ([#2448](https://github.com/MithrilJS/mithril.js/pull/2448) [@isiahmeadows](https://github.com/isiahmeadows))
 
 ---
 

docs/parsePathname.md

@@ -32,11 +32,15 @@ Argument     | Type     | Required | Description
 
 ### How it works
 
-The `m.parsePathname` method creates an object from a path with a possible query string and hash string. It is useful for parsing a URL into more sensible paths, and it's what [`m.route`](route.md) uses internally to normalize paths to later match them. It uses [`m.parseQueryString`](parseQueryString.md) to parse the query parameters into an object.
+The `m.parsePathname` method creates an object from a path with a possible query string. It is useful for parsing a local path name into its parts, and it's what [`m.route`](route.md) uses internally to normalize paths to later match them. It uses [`m.parseQueryString`](parseQueryString.md) to parse the query parameters into an object.
 
 ```javascript
-var data = m.parsePathname("/path/user?a=hello&b=world#random=hash&some=value")
+var data = m.parsePathname("/path/user?a=hello&b=world")
 
 // data.path is "/path/user"
-// data.params is {a: "hello", b: "world", random: "hash", some: "value"}
+// data.params is {a: "hello", b: "world"}
 ```
+
+### General-purpose URL parsing
+
+The method is called `parsePathname` because it applies to pathnames. If you want a general-purpose URL parser, you should use [the global `URL` class](https://developer.mozilla.org/en-US/docs/Web/API/URL) instead.

docs/parseQueryString.md

@@ -19,13 +19,12 @@ var object = m.parseQueryString("a=1&b=2")
 
 ### Signature
 
-`object = m.parseQueryString(string, object)`
+`object = m.parseQueryString(string)`
 
 Argument     | Type                                       | Required | Description
 ------------ | ------------------------------------------ | -------- | ---
 `string`     | `String`                                   | Yes      | A querystring
-`object`     | `Object`                                   | No       | An existing key-value map to merge values into, potentially from a previous `m.parseQueryString` call
-**returns**  | `Object`                                   |          | A key-value map, `object` if provided
+**returns**  | `Object`                                   |          | A key-value map
 
 [How to read signatures](signatures.md)
 

docs/paths.md

@@ -123,7 +123,7 @@ m.route(document.body, "/edit/1", {
 })
 ```
 
-Note that query parameters are implicit - you don't need to name them to accept them. You can match based on an existing value, like in `"/edit?type=image"`, but you don't need to use `"/edit?type=:type"` to accept the value. In fact, Mithril would treat that as you trying to literally match against `m.route.param("type") === ":type"`. Or in summary, use `m.route.param("key")` to extract parameters - it simplifies things.
+Query parameters are implicitly consumed - you don't need to name them to accept them. You can match based on an existing value, like in `"/edit?type=image"`, but you don't need to use `"/edit?type=:type"` to accept the value. In fact, Mithril would treat that as you trying to literally match against `m.route.param("type") === ":type"`, so you probably don't want to do that. In short, use `m.route.param("key")` or route component attributes to read query parameters.
 
 ### Path normalization