Make data files preserve dots in keys instead of using them as paths

Fixes 11ty#1242
Fixes 11ty/11ty-website#639

src/TemplateData.js

@@ -130,12 +130,12 @@ class TemplateData {
     let paths = [
       `${dir}/**/*.json`, // covers .11tydata.json too
       `${dir}/**/*${this.config.jsDataFileSuffix}.cjs`,
-      `${dir}/**/*${this.config.jsDataFileSuffix}.js`
+      `${dir}/**/*${this.config.jsDataFileSuffix}.js`,
     ];
 
     if (this.hasUserDataExtensions()) {
       let userPaths = this.getUserDataExtensions().map(
-        extension => `${dir}/**/*.${extension}` // covers .11tydata.{extension} too
+        (extension) => `${dir}/**/*.${extension}` // covers .11tydata.{extension} too
       );
       paths = userPaths.concat(paths);
     }
@@ -146,7 +146,7 @@ class TemplateData {
   async getTemplateJavaScriptDataFileGlob() {
     let dir = await this.getInputDir();
     return TemplatePath.addLeadingDotSlashArray([
-      `${dir}/**/*${this.config.jsDataFileSuffix}.js`
+      `${dir}/**/*${this.config.jsDataFileSuffix}.js`,
     ]);
   }
 
@@ -182,7 +182,7 @@ class TemplateData {
     fsBench.before();
     let paths = await fastglob(await this.getGlobalDataGlob(), {
       caseSensitiveMatch: false,
-      dot: true
+      dot: true,
     });
     fsBench.after();
 
@@ -211,7 +211,12 @@ class TemplateData {
     let folders = parsed.dir ? parsed.dir.split("/") : [];
     folders.push(parsed.name);
 
-    return folders.join(".");
+    // Folders reduce to `folder["subfolder"]["subsubfolder"]`...
+    const reduction = folders.reduce((acc, cur, i) =>
+      i === 0 ? cur : `${acc}["${cur}"]`
+    );
+
+    return reduction;
   }
 
   async getAllGlobalData() {