diff --git a/shell/cdimage.ts b/shell/cdimage.ts
index a96af2c..899012b 100644
--- a/shell/cdimage.ts
+++ b/shell/cdimage.ts
@@ -9,7 +9,7 @@ namespace CDImage {
 
         private constructor(private sectorReader: Reader, private pvd: PVD) {
             if (this.pvd.type !== 1)
-                throw ('PVD not found');
+                throw new Error('PVD not found');
         }
 
         volumeLabel(): string {
@@ -47,7 +47,7 @@ namespace CDImage {
                     position += child.length;
                 }
                 if (position > 2048)
-                    throw ('dirent across sector boundary');
+                    throw new Error('dirent across sector boundary');
                 if (position === 2048) {
                     sector++;
                     position = 0;
@@ -173,7 +173,7 @@ namespace CDImage {
                             this.tracks[currentTrack].index[Number(fields[1])] = fields[2];
                         break;
                     default:
-                        ; // Do nothing
+                        // Do nothing
                 }
             }
         }
@@ -204,7 +204,7 @@ namespace CDImage {
         }
     }
 
-    enum MdsTrackMode { Audio = 0xa9, Mode1 = 0xaa };
+    enum MdsTrackMode { Audio = 0xa9, Mode1 = 0xaa }
 
     class MdfMdsReader extends ImageReaderBase implements Reader {
         private tracks: Array<{ mode: number; sectorSize: number; offset: number; sectors: number; }>;
@@ -218,7 +218,7 @@ namespace CDImage {
 
             let signature = ASCIIArrayToString(new Uint8Array(buf, 0, 16));
             if (signature !== 'MEDIA DESCRIPTOR')
-                throw mdsFile.name + ': not a mds file';
+                throw new Error(mdsFile.name + ': not a mds file');
 
             let header = new DataView(buf, 0, 0x70);
             let entries = header.getUint8(0x62);
@@ -236,7 +236,7 @@ namespace CDImage {
                     this.tracks[track] = { mode, sectorSize, offset, sectors };
             }
             if (this.tracks[1].mode !== MdsTrackMode.Mode1)
-                throw 'track 1 is not mode1';
+                throw new Error('track 1 is not mode1');
         }
 
         readSector(sector: number): Promise<ArrayBuffer> {
diff --git a/shell/loader.ts b/shell/loader.ts
index faeae70..c102dfc 100644
--- a/shell/loader.ts
+++ b/shell/loader.ts
@@ -65,7 +65,7 @@ namespace xsystem35 {
                 ptr += chunk.byteLength;
             }
             if (ptr !== entry.size)
-                throw ('expected ' + entry.size + ' bytes, but read ' + ptr + 'bytes');
+                throw new Error('expected ' + entry.size + ' bytes, but read ' + ptr + 'bytes');
         }
 
         private async startLoad() {
diff --git a/shell/settings.ts b/shell/settings.ts
index d5896a2..554b377 100644
--- a/shell/settings.ts
+++ b/shell/settings.ts
@@ -29,7 +29,7 @@ namespace xsystem35 {
 
         private checkSaveData() {
             xsystem35.saveDirReady.then(() => {
-                if ((<string[]>FS.readdir('/save')).some((name) => { return name.toLowerCase().endsWith('.asd'); }))
+                if ((<string[]>FS.readdir('/save')).some((name) => name.toLowerCase().endsWith('.asd')))
                     $('#downloadSaveData').removeAttribute('disabled');
             });
         }
@@ -80,7 +80,7 @@ namespace xsystem35 {
                 } else if (file.name.toLowerCase().endsWith('.asd')) {
                     addSaveFile(file.name, await readFileAsArrayBuffer(file));
                 } else {
-                    throw('Unknown file type: ' + file.name);
+                    throw new Error('Unknown file type: ' + file.name);
                 }
                 xsystem35.shell.syncfs(0);
                 xsystem35.shell.addToast('セーブデータの復元に成功しました。', 'success');
diff --git a/shell/tslint.json b/shell/tslint.json
index 5d99943..88e7a73 100644
--- a/shell/tslint.json
+++ b/shell/tslint.json
@@ -6,11 +6,13 @@
         "max-classes-per-file": false,
         "member-access": false,
         "member-ordering": false,
+        "no-angle-bracket-type-assertion": false,
         "no-bitwise": false,
         "no-empty": false,
         "no-namespace": false,
         "no-reference": false,
         "only-arrow-functions": ["allow-declarations", "allow-named-functions"],
+        "prefer-const": false,
         "prefer-for-of": false,
         "quotemark": [true, "single", "avoid-escape"],
         "whitespace": [