Fix for nested multi WACZ loading (#216)

Fix regression introduced during TypeScript conversion
- remove unneeded size var that default to 0, prevented a full load
since never null
- use length instead of size (initial state set to null) in base class
- fixes #215

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@webrecorder/wabac",
-  "version": "2.20.6",
+  "version": "2.20.7",
   "main": "index.js",
   "type": "module",
   "exports": {

src/wacz/ziprangereader.ts

@@ -427,7 +427,6 @@ export class ZipRangeReader {
 export class ZipBlockLoader extends BaseLoader {
   zipreader: ZipRangeReader;
   filename: string;
-  size = 0;
 
   constructor(zipreader: ZipRangeReader, filename: string) {
     super(true);
@@ -442,7 +441,7 @@ export class ZipBlockLoader extends BaseLoader {
   async doInitialFetch(tryHead = false) {
     await this.zipreader.load();
 
-    this.size = this.zipreader.getCompressedSize(this.filename);
+    this.length = this.zipreader.getCompressedSize(this.filename);
 
     let stream: ReadableStream<Uint8Array> | null = null;
 
@@ -459,13 +458,11 @@ export class ZipBlockLoader extends BaseLoader {
   }
 
   async getLength() {
-    // [TODO]
-    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
-    if (this.size === null) {
+    if (this.length === null) {
       await this.doInitialFetch(true);
     }
 
-    return this.size;
+    return this.length || 0;
   }
 
   async getRange(