diff --git a/2023/04/benchmark.js b/2023/04/benchmark.js
new file mode 100644
index 0000000..69b227e
--- /dev/null
+++ b/2023/04/benchmark.js
@@ -0,0 +1,38 @@
+import fs from "fs-extra";
+import { parse } from "yaml";
+import { Bench } from "tinybench";
+import assert from "assert";
+
+import { solution_1 } from "./part1.js";
+import { solution_2 } from "./part2.js";
+
+const input = fs.readFileSync("./input", { encoding: "utf8" });
+const solutions = parse(
+  fs.readFileSync("./solutions.yml", { encoding: "utf8" })
+);
+
+const bench = new Bench({ time: 10000 });
+
+bench
+  .add("1", () => {
+    assert.equal(solution_1(input), solutions[1]);
+  })
+  .add("2", () => {
+    assert.equal(solution_2(input), solutions[2]);
+  });
+
+await bench.run();
+
+bench.tasks.forEach(({ result, name }) => {
+  console.log(
+    JSON.stringify({
+      day: 1,
+      year: 2023,
+      language: "javascript",
+      part: name,
+      timestamp: new Date().toISOString(),
+      time: result.mean / 1000,
+      persec: 1000 / result.mean,
+    })
+  );
+});
diff --git a/2023/04/benchmark.test.js b/2023/04/benchmark.test.js
new file mode 100644
index 0000000..5fb0b6a
--- /dev/null
+++ b/2023/04/benchmark.test.js
@@ -0,0 +1,12 @@
+import { bench, expect } from "vitest";
+import { readFileSync } from "fs-extra";
+import { parse } from "yaml";
+
+import { solution_1 } from "./part1.js";
+
+const input = readFileSync("./input", { encoding: "utf8" });
+const solutions = parse(readFileSync("./solutions.yml", { encoding: "utf8" }));
+
+bench("part 1", () => {
+  expect(solution_1(input)).toBe(solutions[1]);
+});
diff --git a/2023/04/example b/2023/04/example
new file mode 100644
index 0000000..9bdb874
--- /dev/null
+++ b/2023/04/example
@@ -0,0 +1,6 @@
+Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53
+Card 2: 13 32 20 16 61 | 61 30 68 82 17 32 24 19
+Card 3:  1 21 53 59 44 | 69 82 63 72 16 21 14  1
+Card 4: 41 92 73 84 69 | 59 84 76 51 58  5 54 83
+Card 5: 87 83 26 28 32 | 88 30 70 12 93 22 82 36
+Card 6: 31 18 13 56 72 | 74 77 10 23 35 67 36 11
diff --git a/2023/04/part1.js b/2023/04/part1.js
new file mode 100644
index 0000000..5439f5b
--- /dev/null
+++ b/2023/04/part1.js
@@ -0,0 +1,28 @@
+import * as R from "remeda";
+
+export const slice_and_dice = R.createPipe(
+  (l) =>
+    l
+      .replace(/Card \d+:/, "")
+      .split("|")
+      .map((segment) => segment.split(" ").filter(R.identity)),
+  ([winning, mine]) => {
+    let seen = {};
+    winning.forEach((n) => (seen[n] = true));
+    let got = mine.filter((n) => seen[n]).length;
+    return got;
+  },
+  (n) => (n == 0 ? 0 : Math.pow(2, n - 1))
+);
+
+export const get_lines = R.createPipe( (i) => i.split("\n"),
+R.compact);
+
+export function solution_1(input) {
+  return R.pipe(
+    input,
+    get_lines,
+    R.map(slice_and_dice),
+    R.sumBy(R.identity)
+  );
+}
diff --git a/2023/04/part2.js b/2023/04/part2.js
new file mode 100644
index 0000000..914fc35
--- /dev/null
+++ b/2023/04/part2.js
@@ -0,0 +1,31 @@
+import * as R from "remeda";
+
+import { get_lines } from "./part1.js";
+
+export function solution_2(input) {
+    const cards = get_lines(input);
+
+    const cards_won = cards.map(()=>1);
+    let total_won = 0;
+
+    while( cards.length ) {
+    //    console.log(cards_won);
+        let card = cards.shift();
+        const [ winning, mine  ] = card 
+      .replace(/Card \d+:/, "")
+      .split("|")
+      .map((segment) => segment.split(" ").filter(R.identity));
+
+        let seen = {};
+        winning.forEach((n) => (seen[n] = true));
+        let got = mine.filter((n) => seen[n]).length;
+
+        R.range(1,got+1).forEach( i => {
+            cards_won[i] = (cards_won[i] ?? 0 ) +cards_won[0];
+        });
+
+        total_won += cards_won.shift()??0;
+    }
+
+    return total_won;
+}
diff --git a/2023/04/solutions.yml b/2023/04/solutions.yml
new file mode 100644
index 0000000..23a78b7
--- /dev/null
+++ b/2023/04/solutions.yml
@@ -0,0 +1,2 @@
+1: 23678
+2: 15455663
diff --git a/2023/04/test.js b/2023/04/test.js
new file mode 100644
index 0000000..27df077
--- /dev/null
+++ b/2023/04/test.js
@@ -0,0 +1,23 @@
+import { test, expect } from "vitest";
+import { readFileSync } from "fs-extra";
+import { parse } from "yaml";
+
+import { solution_1, slice_and_dice } from "./part1.js";
+import { solution_2 } from "./part2.js";
+
+const input = readFileSync("./input", { encoding: "utf8" });
+const example = readFileSync("./example", { encoding: "utf8" });
+const solutions = parse(readFileSync("./solutions.yml", { encoding: "utf8" }));
+
+test("part 1", () => {
+  expect(
+    slice_and_dice("Card 1: 41 48 83 86 17 | 83 86  6 31 17  9 48 53")
+  ).toBe(8);
+
+  expect(solution_1(example)).toBe(13);
+  expect(solution_1(input)).toBe(solutions["1"]);
+});
+test("part 2", () => {
+  expect(solution_2(example)).toBe(30);
+  expect(solution_2(input)).toBe(solutions["2"]);
+});
diff --git a/2023/benchmark.json b/2023/benchmark.json
index 4d326db..59a284c 100644
--- a/2023/benchmark.json
+++ b/2023/benchmark.json
@@ -6,5 +6,7 @@
 {"language":"perl","timestamp":"2023-12-02T16:40:55","part":2,"day":"2","time":0.00338658146964856,"year":"2023","persec":295.283018867925}
 {"timestamp":"2023-12-02T18:29:20","day":"2","part":1,"variant":"v2","year":"2023","time":0.00388473053892216,"language":"perl","persec":257.418111753372}
 {"day":"2","timestamp":"2023-12-02T18:29:32","part":2,"year":"2023","variant":"v2","persec":258.117195004803,"language":"perl","time":0.00387420915519166}
-{"time":0.00837944664031621,"timestamp":"2023-12-03T20:10:46","parsec":119.339622641509,"day":"3","year":"2023","part":1,"language":"perl"}
-{"year":"2023","day":"3","parsec":4.03940886699507,"language":"perl","part":2,"time":0.247560975609756,"timestamp":"2023-12-03T20:10:59"}
+{"time":0.00837944664031621,"timestamp":"2023-12-03T20:10:46","persec":119.339622641509,"day":"3","year":"2023","part":1,"language":"perl"}
+{"year":"2023","day":"3","persec":4.03940886699507,"language":"perl","part":2,"time":0.247560975609756,"timestamp":"2023-12-03T20:10:59"}
+{"day":4,"year":2023,"language":"javascript","part":"1","timestamp":"2023-12-04T15:22:09.048Z","time":0.0021685645699029317,"persec":461.13452828603647}
+{"day":4,"year":2023,"language":"javascript","part":"2","timestamp":"2023-12-04T15:22:09.052Z","time":0.002291685911610818,"persec":436.3599719025647}
diff --git a/2023/preset/day/preset.ts b/2023/preset/day/preset.ts
index 163677f..abdd037 100644
--- a/2023/preset/day/preset.ts
+++ b/2023/preset/day/preset.ts
@@ -1,13 +1,19 @@
 export default definePreset({
 	name: 'day',
 	options: {
-        perl: true,
+        perl: false,
+        js: false,
 	},
 	handler: async(context) => {
         if( context.options.perl ) {
             await extractTemplates({
                 from: 'perl', whenConflict: 'skip'
             })
+        }
+        if( context.options.js ) {
+            await extractTemplates({
+                from: 'js', whenConflict: 'skip'
+            })
         }
 		// ...
 	},
diff --git a/2023/preset/day/templates/js/benchmark.js b/2023/preset/day/templates/js/benchmark.js
new file mode 100644
index 0000000..5d7fe0c
--- /dev/null
+++ b/2023/preset/day/templates/js/benchmark.js
@@ -0,0 +1,33 @@
+import fs from 'fs-extra';
+import { parse } from 'yaml';
+import { Bench } from 'tinybench';
+import assert from 'assert';
+
+import { solution_1 } from './part1.js';
+import { solution_2 } from './part2.js';
+
+const input = fs.readFileSync('./input',{ encoding: 'utf8'});
+const solutions = parse( fs.readFileSync('./solutions.yml',{encoding:'utf8'}));
+
+const bench = new Bench({time: 10000});
+
+bench.add( '1', () => {
+    assert.equal(solution_1(input),solutions[1])
+})
+.add( '2', () => {
+    assert.equal(solution_2(input),solutions[2])
+});
+
+await bench.run();
+
+bench.tasks.forEach( ({result,name}) => {
+    console.log(JSON.stringify({
+        day : 1,
+        year : 2023,
+        language: 'javascript',
+        part: name,
+        timestamp: new Date().toISOString(),
+        time: result.mean / 1000,
+        persec: 1000 / result.mean,
+    }));
+})
diff --git a/2023/preset/day/templates/js/benchmark.test.js b/2023/preset/day/templates/js/benchmark.test.js
new file mode 100644
index 0000000..4ec0bda
--- /dev/null
+++ b/2023/preset/day/templates/js/benchmark.test.js
@@ -0,0 +1,13 @@
+import { bench, expect } from 'vitest';
+import { readFileSync } from 'fs-extra';
+import { parse } from 'yaml';
+
+import { solution_1 } from './part1.js';
+
+const input = readFileSync('./input',{ encoding: 'utf8'});
+const solutions = parse( readFileSync('./solutions.yml',{encoding:'utf8'}));
+
+bench( 'part 1', () => {
+    expect(solution_1(input)).toBe(solutions[1])
+});
+
diff --git a/2023/preset/day/templates/js/part1.js b/2023/preset/day/templates/js/part1.js
new file mode 100644
index 0000000..2520ce0
--- /dev/null
+++ b/2023/preset/day/templates/js/part1.js
@@ -0,0 +1,6 @@
+import * as R from 'remeda';
+
+
+export function solution_1(input) {
+
+}
diff --git a/2023/preset/day/templates/js/part2.js b/2023/preset/day/templates/js/part2.js
new file mode 100644
index 0000000..0eb2b95
--- /dev/null
+++ b/2023/preset/day/templates/js/part2.js
@@ -0,0 +1,5 @@
+import * as R from 'remeda';
+
+import { } from './part1.js';
+
+export function solution_2(input){}
diff --git a/2023/preset/day/templates/js/test.js b/2023/preset/day/templates/js/test.js
new file mode 100644
index 0000000..5649d82
--- /dev/null
+++ b/2023/preset/day/templates/js/test.js
@@ -0,0 +1,16 @@
+import { test, expect } from 'vitest';
+import { readFileSync } from 'fs-extra';
+import { parse } from 'yaml';
+
+import { solution_1 } from './part1.js';
+import { solution_2 } from './part2.js';
+
+const input = readFileSync('./input',{ encoding: 'utf8'});
+const solutions = parse( readFileSync('./solutions.yml',{encoding:'utf8'}));
+
+test( 'part 1', () => {
+    expect( solution_1(input)).toBe(solutions['1']);
+})
+test( 'part 2', () => {
+    expect( solution_2(input)).toBe(solutions['2']);
+})