fix: fix URL support for path argument of readFile and readFileSync

src/__tests__/volume.test.ts

@@ -1,7 +1,7 @@
+import {URL} from 'url';
 import {Link, Node, Stats, Dirent} from "../node";
 import {Volume, filenameToSteps, StatWatcher} from "../volume";
 
-
 describe('volume', () => {
     describe('filenameToSteps(filename): string[]', () => {
         it('/ -> []', () => {
@@ -432,6 +432,10 @@ describe('volume', () => {
                 expect(buf).toBeInstanceOf(Buffer);
                 expect(str).toBe(data);
             });
+            it('Read file with path passed as URL', () => {
+                const str = vol.readFileSync(new URL('file:///text.txt')).toString();
+                expect(str).toBe(data);
+            });
             it('Specify encoding as string', () => {
                 const str = vol.readFileSync('/text.txt', 'utf8');
                 expect(str).toBe(data);

src/volume.ts

@@ -1018,13 +1018,14 @@ export class Volume {
     private readFileBase(id: TFileId, flagsNum: number, encoding: TEncoding): Buffer | string {
         let result: Buffer | string;
 
-        const userOwnsFd = isFd(id);
+        const isUserFd = typeof id === 'number';
+        let userOwnsFd: boolean = isUserFd && isFd(id);
         let fd: number;
 
-        if(userOwnsFd) {
-            fd = id as number;
-        } else {
-            const steps = filenameToSteps(id as string);
+        if(userOwnsFd) fd = id as number;
+        else {
+            const filename = pathToFilename(id as TFilePath);
+            const steps = filenameToSteps(filename);
             const link: Link = this.getResolvedLink(steps);
 
             if(link) {