Graph calculator improvmentes

frontend/app/utils/routes.ts

@@ -64,3 +64,35 @@ export function versionHref(identity: string, language?: string): string {
 export function isReadingSurface(path: string): boolean {
   return isReaderPath(path) || WIKI_SUB_PATH.test(path) || path === '/new'
 }
+
+/* ---------- the wiki's own pages ----------
+
+   The link map and the graphing calculator are pages the shelf holds no
+   copies of — but the book can read them too. Each has one plain address of
+   its own, and useArticleTabs can lay it on the row beside the open articles:
+   the page then draws the live surface instead of an article, for as long as
+   its page stays open. */
+
+export type ToolPage = 'graph' | 'calculator'
+
+const TOOL_PAGE_PATHS: Record<ToolPage, string> = {
+  graph: '/graph',
+  calculator: '/calculator',
+}
+
+/** The address a tool page lives at. */
+export function toolHref(page: ToolPage): string {
+  return TOOL_PAGE_PATHS[page]
+}
+
+/** Which tool page an address names, if any. */
+export function toolFromPath(path: string): ToolPage | null {
+  const clean = path.replace(/\/+$/, '')
+  for (const page of Object.keys(TOOL_PAGE_PATHS) as ToolPage[])
+    if (clean === TOOL_PAGE_PATHS[page]) return page
+  return null
+}
+
+export function isToolPath(path: string): boolean {
+  return toolFromPath(path) !== null
+}