Archify Diagram Viewer 0.1.0

VS Code extension that previews Archify diagrams from their JSON sources
(live, as you type) and opens rendered Archify HTML in a viewer tab.
Bundles the Archify 3.0.1 renderer and runs it on VS Code's Node runtime.
Adds validation diagnostics, JSON schema help, source-link navigation,
export saving, render-to-file and open-in-browser commands.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/jsonPointer.ts

@@ -0,0 +1,39 @@
+import { findNodeAtLocation, Node, parseTree } from 'jsonc-parser';
+
+export interface OffsetRange {
+  start: number;
+  end: number;
+}
+
+/** Splits an RFC 6901 JSON pointer into path segments. */
+export function pointerSegments(pointer: string): (string | number)[] {
+  if (!pointer || pointer === '/') return [];
+  return pointer
+    .replace(/^\//, '')
+    .split('/')
+    .map((raw) => raw.replace(/~1/g, '/').replace(/~0/g, '~'))
+    .map((segment) => (/^(0|[1-9]\d*)$/.test(segment) ? Number(segment) : segment));
+}
+
+/**
+ * Maps a JSON pointer to a text range. Objects and arrays resolve to their
+ * property key (or opening bracket) so a "missing property" error does not
+ * underline a whole block. Unresolvable paths fall back to the deepest
+ * ancestor that exists.
+ */
+export function rangeForPointer(text: string, pointer: string | undefined): OffsetRange {
+  const root = parseTree(text, [], { allowTrailingComma: true });
+  if (!root) return { start: 0, end: 0 };
+  const segments = pointerSegments(pointer ?? '');
+  let node: Node | undefined;
+  for (let length = segments.length; length >= 0 && !node; length -= 1) {
+    node = findNodeAtLocation(root, segments.slice(0, length));
+  }
+  if (!node) return { start: 0, end: 0 };
+  if (node.type === 'object' || node.type === 'array') {
+    const key = node.parent?.type === 'property' ? node.parent.children?.[0] : undefined;
+    if (key) return { start: key.offset, end: key.offset + key.length };
+    return { start: node.offset, end: node.offset + 1 };
+  }
+  return { start: node.offset, end: node.offset + node.length };
+}