Method getRazorUsings

src/resolution/index.ts:2116–2136

* Collect the `@using` namespaces in scope for a `.razor`/`.cshtml` file: its * own `@using` directives plus every `_Imports.razor` from the file's folder up * to the project root (Razor `_Imports` cascade). Cached per file.

(filePath: string)

   * to the project root (Razor `_Imports` cascade). Cached per file.
   */
  private getRazorUsings(filePath: string): string[] {
    const cached = this.razorUsingsCache.get(filePath);
    if (cached) return cached;
    const usings = new Set<string>();
    const addFrom = (src: string | null): void => {
      if (!src) return;
      for (const m of src.matchAll(/^\s*@using\s+(?:static\s+)?([A-Za-z_][\w.]*)/gm)) usings.add(m[1]!);
    };
    addFrom(this.context.readFile(filePath));
    let dir = filePath.includes('/') ? filePath.slice(0, filePath.lastIndexOf('/')) : '';
    // Walk up to the project root, reading each level's _Imports.razor.
    for (;;) {
      addFrom(this.context.readFile(dir ? `${dir}/_Imports.razor` : '_Imports.razor'));
      if (!dir) break;
      const slash = dir.lastIndexOf('/');
      dir = slash >= 0 ? dir.slice(0, slash) : '';
    }
    const arr = [...usings];
    this.razorUsingsCache.set(filePath, arr);
    return arr;
  }

  /**
   * Resolve a Razor/Blazor simple type ref through the file's `@using`