Implements anchor awareness.

redesign/forum.nim

@@ -58,7 +58,14 @@ proc render(): VNode =
       ),
       r("/t/@id",
         (params: Params) =>
-          (renderPostList(params["id"].parseInt(), isLoggedIn()))
+          (
+            let postId = getInt(($state.url.hash).substr(1), 0);
+            renderPostList(
+              params["id"].parseInt(),
+              if postId == 0: none[int]() else: some[int](postId),
+              isLoggedIn()
+            )
+          )
       ),
       r("/", (params: Params) => renderThreadList())
     ])

redesign/karaxutils.nim

@@ -1,6 +1,25 @@
-import strutils, options, strformat
+import strutils, options, strformat, parseutils
 import dom except window
 
+proc parseInt*(s: string, value: var int, validRange: Slice[int]) {.
+  noSideEffect.} =
+  ## parses `s` into an integer in the range `validRange`. If successful,
+  ## `value` is modified to contain the result. Otherwise no exception is
+  ## raised and `value` is not touched; this way a reasonable default value
+  ## won't be overwritten.
+  var x = value
+  try:
+    discard parseutils.parseInt(s, x, 0)
+  except OverflowError:
+    discard
+  if x in validRange: value = x
+
+proc getInt*(s: string, default = 0): int =
+  ## Safely parses an int and returns it.
+  result = default
+  parseInt(s, result, 0..1_000_000_000)
+
+when defined(js):
   include karax/prelude
   import karax / [kdom]
 

redesign/postlist.nim

@@ -12,6 +12,8 @@ type
     posts*: seq[Post]
 
 when defined(js):
+  from dom import nil
+
   include karax/prelude
   import karax / [vstyles, kajax, kdom]
 
@@ -38,7 +40,7 @@ when defined(js):
   var
     state = newState()
 
-  proc onPostList(httpStatus: int, response: kstring) =
+  proc onPostList(httpStatus: int, response: kstring, postId: Option[int]) =
     state.loading = false
     state.status = httpStatus.HttpCode
     if state.status != Http200: return
@@ -48,6 +50,18 @@ when defined(js):
 
     state.list = some(list)
 
+    # The anchor should be jumped to once all the posts have been loaded.
+    if postId.isSome():
+      discard setTimeout(
+        () => (
+          # Would have used scrollIntoView but then the `:target` selector
+          # isn't activated.
+          window.location.hash = "";
+          window.location.hash = "#" & $postId.get()
+        ),
+        100
+      )
+
   proc onMorePosts(httpStatus: int, response: kstring, start: int) =
     state.loading = false
     state.status = httpStatus.HttpCode
@@ -190,13 +204,17 @@ when defined(js):
           tdiv(class="information-title"):
             text diffStr
 
-  proc renderPostList*(threadId: int, isLoggedIn: bool): VNode =
+  proc renderPostList*(threadId: int, postId: Option[int],
+                       isLoggedIn: bool): VNode =
     if state.status != Http200:
       return renderError("Couldn't retrieve posts.")
 
     if state.list.isNone or state.list.get().thread.id != threadId:
-      let uri = makeUri("posts.json", ("id", $threadId))
+      var params = @[("id", $threadId)]
-      ajaxGet(uri, @[], (s: int, r: kstring) => onPostList(s, r))
+      if postId.isSome():
+        params.add(("anchor", $postId.get()))
+      let uri = makeUri("posts.json", params)
+      ajaxGet(uri, @[], (s: int, r: kstring) => onPostList(s, r, postId))
 
       return buildHtml(tdiv(class="loading loading-lg"))
 

utils.nim

@@ -7,24 +7,8 @@ from times import getTime, getGMTime, format
 let
   UsernameIdent* = IdentChars # TODO: Double check that everyone follows this.
 
-
+import redesign/karaxutils
-proc parseInt*(s: string, value: var int, validRange: Slice[int]) {.
+export parseInt
-  noSideEffect.} =
-  ## parses `s` into an integer in the range `validRange`. If successful,
-  ## `value` is modified to contain the result. Otherwise no exception is
-  ## raised and `value` is not touched; this way a reasonable default value
-  ## won't be overwritten.
-  var x = value
-  try:
-    discard parseutils.parseInt(s, x, 0)
-  except OverflowError:
-    discard
-  if x in validRange: value = x
-
-proc getInt*(s: string, default = 0): int =
-  ## Safely parses an int and returns it.
-  result = default
-  parseInt(s, result, 0..1_000_000_000)
 
 proc `%`*[T](opt: Option[T]): JsonNode =
   ## Generic constructor for JSON data. Creates a new ``JNull JsonNode``