Add support for checkFlags enum (#118)

Also adds support for clicking on a collapsed tree view label to expand
it rather than having to click on the small arrow next to the label.

site/src/App.css

@@ -269,3 +269,7 @@ a:visited {
 .propertiesViewer .array > .value {
   padding-left: 7px;
 }
+
+.treeViewLabel {
+  cursor: pointer;
+}

site/src/compiler/CompilerApi.ts

@@ -15,6 +15,8 @@ export interface CompilerApi {
   SymbolFlags: typeof ts.SymbolFlags;
   TypeFlags: typeof ts.TypeFlags;
   FlowFlags: typeof ts.FlowFlags;
+  // Internal enum
+  CheckFlags: {};
   tsAstViewer: {
     packageName: CompilerPackageNames;
     cachedSourceFiles: { [name: string]: SourceFile | undefined };

site/src/components/LazyTreeView.tsx

@@ -3,14 +3,16 @@ import TreeView from "react-treeview";
 
 export interface LazyTreeViewProps {
   defaultCollapsed: boolean;
-  nodeLabel: React.ReactNode;
+  nodeLabel: string | undefined;
   getChildren: () => JSX.Element;
 }
 
 export function LazyTreeView(props: LazyTreeViewProps) {
   const [isCollapsed, setIsCollapsed] = useState(props.defaultCollapsed);
 
-  return <TreeView nodeLabel={props.nodeLabel} collapsed={isCollapsed} onClick={toggleState}>{isCollapsed ? undefined : props.getChildren()}</TreeView>;
+  const label = <span className="treeViewLabel" onClick={toggleState}>{props.nodeLabel}</span>
+
+  return <TreeView nodeLabel={label} collapsed={isCollapsed} onClick={toggleState}>{isCollapsed ? undefined : props.getChildren()}</TreeView>;
 
   function toggleState() {
     setIsCollapsed(!isCollapsed);

site/src/components/PropertiesViewer.tsx

@@ -324,6 +324,10 @@ function getCustomValueDiv(context: Context, key: string, value: any, parent: an
     if (isTsSymbol(parent) && key === "flags") {
       return getEnumFlagElement(context.api.SymbolFlags, value);
     }
+    // TS pre-5.0 puts this on the symbol, TS 5.0 puts it on a plain "links" object
+    if (key === "checkFlags" && typeof value === "number") {
+      return getEnumFlagElement(context.api.CheckFlags, value);
+    }
     if (isFlowNode(parent) && key === "flags") {
       return getEnumFlagElement(context.api.FlowFlags, value);
     }