fix: better error message when extracting a file that doesn't exist i…

…n the archive (#286)

lib/filesystem.js

@@ -142,6 +142,10 @@ class Filesystem {
     followLinks = typeof followLinks === 'undefined' ? true : followLinks
     const info = this.getNode(p)
 
+    if (!info) {
+      throw new Error(`"${p}" was not found in this archive`)
+    }
+
     // if followLinks is false we don't resolve symlinks
     if (info.link && followLinks) {
       return this.getFile(info.link)

test/cli-spec.js

@@ -83,6 +83,9 @@ describe('command line interface', function () {
     await execAsar('e test/input/extractthis-unpack.asar tmp/extractthis-unpack-cli/')
     return compDirs('tmp/extractthis-unpack-cli/', 'test/expected/extractthis')
   })
+  it('should throw an error when trying to extract a file that doesn\'t exist in the archive', async () => {
+    await assert.rejects(execAsar('ef test/input/extractthis.asar this-file-doesnt-exist.404'), /"(.*?)" was not found in this archive/)
+  })
   it('should create archive from directory with unpacked dirs', async () => {
     await execAsar('p test/input/packthis/ tmp/packthis-unpack-dir-cli.asar --unpack-dir dir2 --exclude-hidden')
     assert.ok(fs.existsSync('tmp/packthis-unpack-dir-cli.asar.unpacked/dir2/file2.png'))