diff --git a/src/contexts/folding_range.ts b/src/contexts/folding_range.ts
index 5173925..1639432 100644
--- a/src/contexts/folding_range.ts
+++ b/src/contexts/folding_range.ts
@@ -23,6 +23,20 @@ export default class FoldingRangeContext {
     private static readonly nodeFormat = RegExp('^@(?:(node)|(subsection|unnumberedsubsec|appendixsubsec|subheading)|' +
         '(section|unnumberedsec|appendixsec|heading)|(chapter|unnumbered|appendix|majorheading|chapheading)) (.*)$');
 
+    private foldingRanges?: FoldingRange[];
+
+    private nodes = <vscode.CodeLens[]>[];
+
+    private commentRange?: Range;
+
+    private headerStart?: number;
+
+    private closingChapter?: number;
+
+    private closingSection?: number;
+
+    private closingSubsection?: number;
+
     /**
      * Get VSCode folding ranges from the context.
      */
@@ -38,20 +52,6 @@ export default class FoldingRangeContext {
         return this.nodes;
     }
 
-    private foldingRanges?: FoldingRange[];
-
-    private nodes = <vscode.CodeLens[]>[];
-
-    private commentRange?: Range;
-
-    private headerStart?: number;
-
-    private closingChapter?: number;
-
-    private closingSection?: number;
-
-    private closingSubsection?: number;
-
     /**
      * Update folding range context based on document change event.
      * 
@@ -71,6 +71,8 @@ export default class FoldingRangeContext {
         return false;
     }
 
+    constructor(private readonly document: vscode.TextDocument) {}
+
     /**
      * Calculate and update folding ranges for the document.
      * 
@@ -146,8 +148,6 @@ export default class FoldingRangeContext {
         return true;
     }
 
-    constructor(private readonly document: vscode.TextDocument) {}
-
     private processNode(lineText: string, lineNum: number, lastLineNum: number) {
         const result = lineText.match(FoldingRangeContext.nodeFormat);
         if (result === null) return false;
diff --git a/src/contexts/preview.ts b/src/contexts/preview.ts
index 9294731..0bde310 100644
--- a/src/contexts/preview.ts
+++ b/src/contexts/preview.ts
@@ -64,6 +64,30 @@ export default class PreviewContext {
      */
     private pendingUpdate = false;
 
+    private get imageTransformer(): Optional<Operator<string>> {
+        if (!Options.displayImage) return undefined;
+        const pathName = path.dirname(this.document.fileName);
+        return src => {
+            const srcUri = vscode.Uri.file(pathName + '/' + src);
+            // To display images in webviews, image URIs in HTML should be converted to VSCode-recognizable ones.
+            return this.panel.webview.asWebviewUri(srcUri).toString();
+        };
+    }
+
+    private get script() {
+        if (!Options.enableCodeLens) return undefined;
+        return "window.addEventListener('message', event => {" +
+            "const message = event.data;" +
+            "switch (message.command) {" +
+                "case 'goto':" +
+                    "window.location.hash = message.value;" +
+                    // We may want to scroll to the same node again.
+                    "history.pushState('', '', window.location.pathname);" +
+                    "break;" +
+            "}" +
+        "})";
+    }
+
     close() {
         this.disposables.forEach(event => event.dispose());
         this.panel.dispose();
@@ -108,30 +132,6 @@ export default class PreviewContext {
         this.updateWebview();
     }
 
-    private get imageTransformer(): Optional<Operator<string>> {
-        if (!Options.displayImage) return undefined;
-        const pathName = path.dirname(this.document.fileName);
-        return src => {
-            const srcUri = vscode.Uri.file(pathName + '/' + src);
-            // To display images in webviews, image URIs in HTML should be converted to VSCode-recognizable ones.
-            return this.panel.webview.asWebviewUri(srcUri).toString();
-        };
-    }
-
-    private get script() {
-        if (!Options.enableCodeLens) return undefined;
-        return "window.addEventListener('message', event => {" +
-            "const message = event.data;" +
-            "switch (message.command) {" +
-                "case 'goto':" +
-                    "window.location.hash = message.value;" +
-                    // We may want to scroll to the same node again.
-                    "history.pushState('', '', window.location.pathname);" +
-                    "break;" +
-            "}" +
-        "})";
-    }
-
     private updateTitle() {
         const updating = this.updating ? '(Updating) ' : '';
         const fileName = path.basename(this.document.fileName);
diff --git a/src/indicator.ts b/src/indicator.ts
index 8e00734..f02994f 100644
--- a/src/indicator.ts
+++ b/src/indicator.ts
@@ -9,17 +9,28 @@ import * as vscode from 'vscode';
 import Options from './options';
 import { exec } from './utils/misc';
 
+/**
+ * Shows whether GNU Texinfo is properly installed and configured.
+ */
 export default class Indicator implements vscode.Disposable {
 
     private static singleton?: Indicator;
 
-    private statusBarItem: vscode.StatusBarItem;
-
     static async click() {
         await Indicator.instance.updateStatus();
         Indicator.instance.refresh(vscode.window.activeTextEditor);
     }
 
+    static onTextEditorChange(editor?: vscode.TextEditor) {
+        Indicator.instance.refresh(editor);
+    }
+
+    static get instance() {
+        return this.singleton ??= new Indicator();
+    }
+
+    private statusBarItem: vscode.StatusBarItem;
+
     private refresh(editor?: vscode.TextEditor) {
         if (editor === undefined || editor.document.languageId != 'texinfo') {
             this.statusBarItem.hide();
@@ -28,7 +39,7 @@ export default class Indicator implements vscode.Disposable {
         }
     }
 
-    async updateStatus() {
+    private async updateStatus() {
         const output = await exec(Options.makeinfo, ['--version'], Options.maxSize);
         const result = output.data?.match(/\(GNU texinfo\) (.*)\n/);
         let tooltip = '', icon: string, version = '';
@@ -49,14 +60,6 @@ export default class Indicator implements vscode.Disposable {
         this.statusBarItem.command = 'texinfo.indicator.click';
     }
 
-    static onTextEditorChange(editor?: vscode.TextEditor) {
-        Indicator.instance.refresh(editor);
-    }
-
-    static get instance() {
-        return this.singleton ??= new Indicator();
-    }
-
     private constructor() {
         this.statusBarItem = vscode.window.createStatusBarItem(vscode.StatusBarAlignment.Right, 100);
         this.updateStatus().then(() => this.refresh(vscode.window.activeTextEditor));
diff --git a/src/logger.ts b/src/logger.ts
index 18eaf64..c7c18be 100644
--- a/src/logger.ts
+++ b/src/logger.ts
@@ -29,12 +29,12 @@ export default class Logger implements vscode.Disposable {
 
     private outputChannel: vscode.OutputChannel;
 
+    private constructor() {
+        this.outputChannel = vscode.window.createOutputChannel('Texinfo');
+    }
+
     dispose() {
         Logger.instance.outputChannel.dispose();
         Logger.singleton = undefined;
     }
-
-    private constructor() {
-        this.outputChannel = vscode.window.createOutputChannel('Texinfo');
-    }
 }
diff --git a/src/options.ts b/src/options.ts
index 29d9e24..942c9da 100644
--- a/src/options.ts
+++ b/src/options.ts
@@ -74,10 +74,6 @@ export default class Options implements vscode.Disposable {
 
     private readonly configuration: vscode.WorkspaceConfiguration;
 
-    private constructor(section: string) {
-        this.configuration = vscode.workspace.getConfiguration(section);
-    }
-
     private getString(section: string) {
         return this.configuration.get(section, '');
     }
@@ -90,6 +86,10 @@ export default class Options implements vscode.Disposable {
         return this.configuration.get(section, 0);
     }
 
+    private constructor(section: string) {
+        this.configuration = vscode.workspace.getConfiguration(section);
+    }
+
     dispose() {
         Options.singleton = undefined;
     }
diff --git a/src/utils/converter.ts b/src/utils/converter.ts
index 184bf2f..530ae74 100644
--- a/src/utils/converter.ts
+++ b/src/utils/converter.ts
@@ -38,10 +38,7 @@ export default class Converter {
 
     constructor(private readonly path: string) {}
 
-    async convertToHtml(
-        imgTransformer?: Operator<string>,
-        insertScript?: string,
-    ) {
+    async convertToHtml(imgTransformer?: Operator<string>, insertScript?: string) {
         const options = ['-o', '-', '--no-split', '--html', `--error-limit=${Options.errorLimit}`];
         Options.noHeaders && options.push('--no-headers');
         Options.force && options.push('--force');