fix: Address PR feedback.

- Throw if header comment in compiled css file is after footer.
- cssContents should be a string. Also add blockId as a property to the
ImportedCompiledCssFile interface.
- Fix comment for getBlockRelative().

Author: Timothy Lindvall

packages/@css-blocks/core/src/BlockParser/BlockFactory.ts

@@ -296,9 +296,8 @@ export class BlockFactory {
   }
 
   /**
-   * Similar to getBlockFromPath(), this imports and parses a block data file. However,
-   * this method can accept relative paths using a FileIdentifier (generated by an Importer)
-   * as the base location for the relative path.
+   * Similar to getBlock(), this imports and parses a block data file. However, this
+   * method parses a block relative to another block.
    *
    * @param fromIdentifier - The FileIdentifier that references the base location that the
    *                         import path is relative to.

packages/@css-blocks/core/src/importing/BaseImporter.ts

@@ -86,6 +86,10 @@ export abstract class BaseImporter implements Importer {
     }
     const footerEndIndex = footerStartIndex + footerFullMatch.length;
 
+    if (headerStartIndex > footerStartIndex) {
+      throw new Error("Header must exist before footer in imported content.");
+    }
+
     // Break the file into segments.
     const pre = contents.slice(0, headerStartIndex);
     const post = contents.slice(footerEndIndex + 1);

packages/@css-blocks/core/src/importing/Importer.ts

@@ -108,10 +108,16 @@ export interface ImportedCompiledCssFile {
   syntax: Syntax.css;
 
   /**
-   * The contents of the imported pre-compiled CSS file, sliced into segments based
-   * on the presence and location of CSS Blocks comments.
+   * The CSS rules imported from the pre-compiled CSS file.
    */
-  cssContents: ImportedCompiledCssFileContents;
+  cssContents: string;
+
+  /**
+   * The Block ID as declared in the header comment. This is expected
+   * to match the `block-id` declaration for the `:scope` selector
+   * in the definition.
+   */
+  blockId: string;
 
   /**
    * The contents of the block definition. If this was embedded base64 data, it will