imp: release large values early for GC

Author: CTyrannosaurus

lib/xlsx/xlsx.js

@@ -249,11 +249,13 @@ class XLSX {
     if (!stream[Symbol.asyncIterator] && stream.pipe) {
       stream = stream.pipe(new PassThrough());
     }
-    const chunks = [];
+    let chunks = [];
     for await (const chunk of stream) {
       chunks.push(chunk);
     }
-    return this.load(Buffer.concat(chunks), options);
+    const buffer = Buffer.concat(chunks);
+    chunks = null;
+    return this.load(buffer, options);
   }
 
   async load(data, options) {
@@ -282,7 +284,8 @@ class XLSX {
       buffer = await officeCrypto.decrypt(buffer, {password: options.password});
     }
 
-    const zip = await JSZip.loadAsync(buffer);
+    let zip = await JSZip.loadAsync(buffer);
+    buffer = null;
     for (const entry of Object.values(zip.files)) {
       /* eslint-disable no-await-in-loop */
       if (!entry.dir) {
@@ -413,6 +416,7 @@ class XLSX {
         }
       }
     }
+    zip = null;
 
     this.reconcile(model, options);
 

spec/integration/data/extra-large.xlsx

@@ -130,6 +130,24 @@ describe('WorkbookReader', () => {
           {maxRows: 20}
         );
       });
+
+      describe('Big file support', () => {
+        it('should read large file correctly', function(done) {
+          this.timeout(20000);
+          const workbook = new ExcelJS.Workbook();
+          workbook.xlsx
+            .read(
+              fs.createReadStream('./spec/integration/data/extra-large.xlsx')
+            )
+            .then(result => {
+              expect(result._worksheets[1]._rows.length).to.equal(512781);
+              expect(
+                result._worksheets[1]._rows[500000]._cells[4]._value.value
+              ).to.equal(11);
+              done();
+            });
+        });
+      });
     });
   });