Fixed the generation of the "prev" option in JSON generator

composer.json

@@ -8,6 +8,11 @@
             "SymfonyDocsBuilder\\": "src"
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "SymfonyDocsBuilder\\Tests\\": "tests"
+        }
+    },
     "require": {
         "ext-json": "*",
         "ext-curl": "*",

src/BuildResult.php

@@ -3,6 +3,7 @@
 namespace SymfonyDocsBuilder;
 
 use Doctrine\RST\Builder;
+use Doctrine\RST\Meta\Metas;
 use Symfony\Component\Console\Output\NullOutput;
 use Symfony\Component\Filesystem\Filesystem;
 use SymfonyDocsBuilder\BuildConfig;
@@ -14,11 +15,14 @@
 
 class BuildResult
 {
+    private $builder;
     private $errors;
+    private $jsonResults = [];
 
-    public function __construct(array $errors)
+    public function __construct(Builder $builder)
     {
-        $this->errors = $errors;
+        $this->builder = $builder;
+        $this->errors = $builder->getErrorManager()->getErrors();
     }
 
     public function appendError(string $errorMessage): void
@@ -40,4 +44,32 @@ public function getErrors(): array
     {
         return $this->errors;
     }
+
+    public function getMetadata(): Metas
+    {
+        return $this->builder->getMetas();
+    }
+
+    /**
+     * Returns the "master document": the first file whose toctree is parsed.
+     *
+     * Unless customized, this is "index" (i.e. file index.rst).
+     */
+    public function getMasterDocumentFilename(): string
+    {
+        return $this->builder->getIndexName();
+    }
+
+    /**
+     * Returns the JSON array data generated for each file, keyed by the source filename.
+     */
+    public function getJsonResults(): array
+    {
+        return $this->jsonResults;
+    }
+
+    public function setJsonResults(array $jsonResults): void
+    {
+        $this->jsonResults = $jsonResults;
+    }
 }

src/DocBuilder.php

@@ -25,7 +25,7 @@ public function build(BuildConfig $config): BuildResult
         $builder = new Builder(KernelFactory::createKernel($config));
         $builder->build($config->getContentDir(), $config->getOutputDir());
 
-        $buildResult = new BuildResult($builder->getErrorManager()->getErrors());
+        $buildResult = new BuildResult($builder);
 
         $missingFilesChecker = new MissingFilesChecker($config);
         $missingFiles = $missingFilesChecker->getMissingFiles();
@@ -38,13 +38,13 @@ public function build(BuildConfig $config): BuildResult
             $filesystem->dumpFile($config->getOutputDir().'/build_errors.txt', implode("\n", $buildResult->getErrors()));
         }
 
-        $metas = $builder->getMetas();
+        $metas = $buildResult->getMetadata();
         if ($config->getSubdirectoryToBuild()) {
             $htmlForPdfGenerator = new HtmlForPdfGenerator($metas, $config);
             $htmlForPdfGenerator->generateHtmlForPdf();
         } else {
             $jsonGenerator = new JsonGenerator($metas, $config);
-            $jsonGenerator->generateJson();
+            $buildResult->setJsonResults($jsonGenerator->generateJson($builder->getIndexName()));
         }
 
         return $buildResult;