Strip buffers after writing to disk to reduce memory usage (issue #302)

src/image.js

@@ -854,11 +854,26 @@ export default class Image {
           throw e;
         }
       }
+    }).then(results => {
+      // Strip buffers to free memory (only if file was written to disk)
+      if(results) {
+        for(let format in results) {
+          if(Array.isArray(results[format])) {
+            for(let stat of results[format]) {
+              if(stat.outputPath && stat.buffer && !this.options.dryRun) {
+                delete stat.buffer;
+              }
+            }
+          }
+        }
+      }
+      return results;
     });
 
     return this.#queuePromise;
   }
 
+
   // Factory to return from cache if available
   static create(src, options = {}) {
     let img = new Image(src, options);

test/test.js

@@ -1277,3 +1277,14 @@ test("#105 Transparent format output filtering (no minimum transparency formats
   // must include one of: svg, png, or gif
   t.deepEqual(Object.keys(stats), ["webp", "jpeg"]);
 });
+
+test("Buffer should be stripped after writing to disk", async t => {
+  let stats = await eleventyImage("./test/bio-2017.jpg", {
+    formats: ["jpeg"],
+    outputDir: "./test/img/"
+  });
+
+  t.truthy(stats.jpeg[0].width);
+  t.truthy(stats.jpeg[0].outputPath);
+  t.falsy(stats.jpeg[0].buffer);
+});