Support running Benchmark in Browser

src/index.ts

@@ -1,10 +1,7 @@
 import hrtime from "browser-process-hrtime";
 import { EventEmitter } from "events";
 import * as mathjs from "mathjs";
-import { FOOTER, HEADER } from "./etc";
-import { JestReporter, KarmaReporter, MochaReporter } from "./reporters";
-
-export { JestReporter, KarmaReporter, MochaReporter };
+import { FOOTER, HEADER } from "./reporters/utils";
 
 export declare interface BenchmarkEventEmitter {
     emit(event: "record", description: Array<string>, measurement: Measurement): boolean;

src/plugin/jestReporter.ts

@@ -1,3 +1,3 @@
-import { JestReporter } from "..";
+import { JestReporter } from "../reporters/jest";
 
 export = JestReporter;

src/plugin/jestReporterSetup.ts

@@ -1,3 +1,3 @@
-import { JestReporter } from "..";
+import { JestReporter } from "../reporters/jest";
 
 JestReporter.initializeKelonio();

src/plugin/karmaReporter.ts

@@ -1,4 +1,4 @@
-import { KarmaReporter } from "..";
+import { KarmaReporter } from "../reporters/karma";
 
 module.exports = {
     "reporter:kelonio": ["type", KarmaReporter],

src/plugin/karmaReporterSetup.ts

@@ -1,3 +1,3 @@
-import { KarmaReporter } from "..";
+import { KarmaReporter } from "../reporters/karma";
 
 KarmaReporter.initializeKelonio();

src/plugin/mochaReporter.ts

@@ -1,3 +1,3 @@
-import { MochaReporter } from "..";
+import { MochaReporter } from "../reporters/mocha";
 
 export = MochaReporter;

src/reporters/jest.ts

@@ -0,0 +1,111 @@
+import * as fsModule from "fs";
+import { Benchmark, benchmark } from '../index'
+import { ExtensionLookup, handleExtraReports } from "./utils";
+
+export const STATE_FILE = ".kelonio.state.json";
+
+let fs: typeof fsModule;
+let canUseFs = true;
+try {
+    fs = require("fs");
+} catch {
+    canUseFs = false;
+}
+
+export class BenchmarkFileState {
+    constructor() {
+        if (!canUseFs) {
+            throw new Error("Unable to access file system");
+        }
+    }
+
+    exists(): boolean {
+        return fs.existsSync(STATE_FILE);
+    }
+
+    read(): any {
+        return JSON.parse(fs.readFileSync(STATE_FILE, "utf-8"));
+    }
+
+    write(data: object): void {
+        fs.writeFileSync(STATE_FILE, JSON.stringify(data), "utf-8");
+    }
+
+    append(data: object): void {
+        let previousData;
+        try {
+            previousData = this.read();
+        } catch {
+            previousData = {};
+        }
+        this.write({ ...previousData, ...data });
+    }
+
+    delete(): void {
+        try {
+            fs.unlinkSync(STATE_FILE);
+        } catch {}
+    }
+}
+
+interface JestReporterOptions {
+    keepStateAtStart?: boolean;
+    keepStateAtEnd?: boolean;
+    printReportAtEnd?: boolean;
+    extensions?: Array<ExtensionLookup>;
+}
+
+export class JestReporter implements jest.Reporter {
+    options: JestReporterOptions = {
+        keepStateAtStart: false,
+        keepStateAtEnd: false,
+        printReportAtEnd: true,
+    };
+    constructor(testData?: any, options?: JestReporterOptions) {
+        if (options) {
+            this.options = { ...this.options, ...options };
+        }
+    }
+    static initializeKelonio(): void {
+        const state = new BenchmarkFileState();
+        benchmark.events.on("record", (description, measurement) => {
+            const b = new Benchmark();
+            if (state.exists()) {
+                b.data = state.read();
+            }
+            b.incorporate(description, measurement);
+            state.write(b.data);
+        });
+    }
+
+    onRunStart(): void {
+        const state = new BenchmarkFileState();
+        if (this.options.keepStateAtStart) {
+            state.append({});
+        } else {
+            state.write({});
+        }
+    }
+
+    onRunComplete(): void {
+        const state = new BenchmarkFileState();
+        if (!state.exists()) {
+            throw new Error(
+                "The Kelonio reporter for Jest requires benchmark serialization." +
+                    " Make sure to call `JestReporter.initializeKelonio()`."
+            );
+        }
+
+        const b = new Benchmark();
+        b.data = state.read();
+
+        if (this.options.printReportAtEnd) {
+            console.log(`\n${b.report()}`);
+            handleExtraReports(this.options.extensions, b, console.log);
+        }
+
+        if (!this.options.keepStateAtEnd) {
+            state.delete();
+        }
+    }
+}