refactor: replace html-minifier with html-minifier-terser to remove dependency on uglify and support ES6 and newer (#10)

Author: mellster2012

package.json

@@ -32,7 +32,7 @@
   },
   "homepage": "https://github.com/fugle-dev/fugle-backtest-node#readme",
   "dependencies": {
-    "html-minifier": "^4.0.0",
+    "html-minifier-terser": "^7.2.0",
     "lodash": "^4.17.21",
     "luxon": "^3.2.1",
     "open": "^8.4.1"
@@ -41,6 +41,7 @@
     "@commitlint/cli": "^16.2.1",
     "@commitlint/config-conventional": "^16.2.1",
     "@types/html-minifier": "^4.0.2",
+    "@types/html-minifier-terser": "^7.0.2",
     "@types/jest": "^27.0.1",
     "@types/lodash": "^4.14.191",
     "@types/luxon": "^3.2.0",

src/plotting.ts

@@ -1,7 +1,7 @@
 import * as fs from 'fs';
 import * as assert from 'assert';
 import * as open from 'open';
-import { minify } from 'html-minifier';
+import { minify } from 'html-minifier-terser';
 import { Stats } from './stats';
 import { PlottingOptions } from './interfaces';
 
@@ -16,17 +16,14 @@ export class Plotting {
     this.filename = options?.filename?.toLowerCase() ?? 'output.html';
   }
 
-  public plot() {
-    const html = minify(this.createHTML(), {
-      collapseWhitespace: true,
-      removeComments: true,
-      collapseBooleanAttributes: true,
-      useShortDoctype: true,
-      removeEmptyAttributes: true,
-      removeOptionalTags: true,
-      minifyJS: true
-    });
-    const outputFile = this.filename.endsWith('.html') ? `./${this.filename}` : `./${this.filename}.html`;
+  public async getHTML() {
+    return await minify(this.createHTML());
+  }
+
+  public async plot() {
+    const html = await minify(this.createHTML());
+    let outputFile = this.filename.startsWith('/') || this.filename.startsWith('./') ? this.filename : `./${this.filename}`;
+    if (! outputFile.endsWith('.html')) outputFile = outputFile + '.html';
     fs.writeFileSync(outputFile, html);
 
     if (this.openBrowser) open(outputFile);

src/stats.ts

@@ -172,11 +172,18 @@ export class Stats {
     this.results.print();
   }
 
-  public plot() {
+  public async plot() {
     if (!this.results) {
       throw new Error('No stats results');
     }
-    new Plotting(this, { openBrowser: this.options.openBrowser, filename: this.options.filename }).plot();
+    await new Plotting(this, { openBrowser: this.options.openBrowser, filename: this.options.filename }).plot();
+  }
+
+  public async toHTML() {
+    if (!this.results) {
+      throw new Error('No stats results');
+    }
+    return await new Plotting(this).getHTML();
   }
 
   private computeExposureTime(index: string[], tradeLog: DataFrame) {

test/plotting.spec.ts

@@ -1,13 +1,13 @@
 import * as open from 'open';
-import { minify } from 'html-minifier';
+import { minify } from 'html-minifier-terser';
 import { Plotting } from '../src/plotting';
 import { Backtest } from '../src/backtest';
 import { Stats } from '../src/stats';
 import { SmaCross } from './sma-cross.strategy';
 
 jest.mock('fs');
 jest.mock('open');
-jest.mock('html-minifier');
+jest.mock('html-minifier-terser');
 
 describe('Plotting', () => {
   let backtest: Backtest;
@@ -47,18 +47,18 @@ describe('Plotting', () => {
   });
 
   describe('.plot()', () => {
-    it('should create the HTML file with minified content', () => {
-      const options = { openBrowser: false, filename: 'test.html' };
+    it('should create the HTML file with minified content', async () => {
+      const options = {openBrowser: false, filename: 'test.html'};
       const plotting = new Plotting(stats, options);
-      plotting.plot();
+      await plotting.plot();
       expect(minify).toHaveBeenCalled();
       expect(open).not.toBeCalled();
     });
 
-    it('should create the HTML file with minified content and open it in the browser', () => {
-      const options = { openBrowser: true, filename: 'test.html' };
+    it('should create the HTML file with minified content and open it in the browser', async () => {
+      const options = {openBrowser: true, filename: 'test.html'};
       const plotting = new Plotting(stats, options);
-      plotting.plot();
+      await plotting.plot();
       expect(minify).toHaveBeenCalled();
       expect(open).toHaveBeenCalledWith(`./${options.filename}`);
     });

test/stats.spec.ts

@@ -73,19 +73,19 @@ describe('Stats', () => {
   });
 
   describe('.plot()', () => {
-    it('should plot the equity curve', () => {
-      const stats = new Stats(data, strategy, equity, trades, { riskFreeRate: 0 });
+    it('should plot the equity curve', async () => {
+      const stats = new Stats(data, strategy, equity, trades, {riskFreeRate: 0});
       stats.compute();
       Plotting.prototype.plot = jest.fn();
-      stats.plot();
+      await stats.plot();
       expect(Plotting.prototype.plot).toBeCalled();
     });
 
-    it('should throw error when missing results', () => {
-      expect(() => {
-        const stats = new Stats(data, strategy, equity, trades, { riskFreeRate: 0 });
-        stats.plot();
-      }).toThrow(Error);
+    it('should throw error when missing results', async () => {
+      await expect(async () => {
+        const stats = new Stats(data, strategy, equity, trades, {riskFreeRate: 0});
+        await stats.plot();
+      }).rejects.toThrow(Error);
     });
   });
 });