diff --git a/javascript/.gitignore b/javascript/.gitignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/javascript/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/javascript/index.js b/javascript/index.js
new file mode 100644
index 0000000..6b40dbf
--- /dev/null
+++ b/javascript/index.js
@@ -0,0 +1,170 @@
+'use strict'
+
+exports.parseDeck = parseDeck
+exports.encodeDeck = encodeDeck
+
+const b64 = require('base64-js')
+
+const CURRENT_VERSION = 2
+const ENCODE_PREFIX = "ADC"
+
+
+function encodeDeck(deck) {
+    if (!deck || !deck.heroes || !deck.cards) throw "invalid deck"
+
+    const heroes = deck.heroes.sort((a, b) => a.id - b.id)
+    const cards = deck.cards.sort((a, b) => a.id - b.id)
+
+    const encoder = cardEncoder()
+    encoder.writeVar(heroes.length, 3)
+    heroes.forEach(it => encoder.writeCard(it.id, it.turn))
+    encoder.resetPreviousId()
+    cards.forEach(it => encoder.writeCard(it.id, it.count))
+
+    const versionAndHeroes = CURRENT_VERSION << 4 | extractNBitsWithCarry(heroes.length, 3)
+    const checksum = computeChecksum(encoder.getBytes())
+    const name = (deck.name || "").substr(0, 63)
+
+    const header = [versionAndHeroes, checksum, name.length]
+    const nameArray = Array.apply(null, { length: name.length }).map((_, i) => name.charCodeAt(i))
+
+    const encodedDeck = b64.fromByteArray(header.concat(encoder.getBytes(), nameArray))
+    const sanitizedDeckCode = ENCODE_PREFIX + encodedDeck.replace(/\//g, "-").replace(/=/g, "_")
+
+    return sanitizedDeckCode
+}
+
+function cardEncoder() {
+    const bytes = []
+    var previousId = 0
+
+    function writeVar(value, bitsToSkip) {
+        if (value < (1 << bitsToSkip)) return
+        value = value >>> bitsToSkip
+        while (value > 0) {
+            bytes.push(extractNBitsWithCarry(value, 7))
+            value = value >>> 7
+        }
+    }
+
+    function writeCard(id, n) {
+        const nPart = n <= 3 ? n - 1 : 3
+
+        const delta = id - previousId
+        previousId = id
+        const idPart = extractNBitsWithCarry(delta, 5)
+
+        bytes.push((nPart << 6) | idPart)
+        writeVar(delta, 5)
+        if (n > 3) writeVar(n, 0)
+    }
+
+    return {
+        writeVar,
+        writeCard,
+        resetPreviousId: () => previousId = 0,
+        getBytes: () => bytes
+    }
+}
+
+function extractNBitsWithCarry(value, bits) {
+    const limitBit = 1 << bits
+    if (value < limitBit) return value
+    return limitBit | (value & (limitBit - 1))
+}
+
+
+
+function parseDeck(deckCode) {
+    if (!deckCode.startsWith(ENCODE_PREFIX)) throw "invalid deck code prefix"
+    const b64Str = deckCode.substr(ENCODE_PREFIX.length)
+        .replace(/-/g, "/")
+        .replace(/_/g, "=")
+
+    const deckCodeBytes = b64.toByteArray(b64Str)
+
+    var byteIndex = 0
+
+    const versionAndHeroes = deckCodeBytes[byteIndex++]
+    const version = versionAndHeroes >>> 4
+    const checksum = deckCodeBytes[byteIndex++]
+    const stringLength = version > 1 ? deckCodeBytes[byteIndex++] : 0
+
+    if (version > CURRENT_VERSION) throw `deck code version ${version} is not supported`
+
+
+    const nameStartIndex = deckCodeBytes.length - stringLength
+    const deckBytes = deckCodeBytes.slice(byteIndex, nameStartIndex)
+    const computedChecksum = computeChecksum(deckBytes)
+    if (checksum != computedChecksum) throw "invalid deck code checksum"
+
+    const decoder = cardDecoder(deckBytes)
+
+    const heroesLength = decoder.readVar(versionAndHeroes, 3)
+    const heroes = []
+    for (let i = 0; i < heroesLength; i++) {
+        heroes.push(decoder.readCard("turn"))
+    }
+
+    decoder.resetPreviousId()
+    const cards = []
+    while (decoder.hasNext()) {
+        cards.push(decoder.readCard("count"))
+    }
+
+    const name = String.fromCharCode.apply(null, deckCodeBytes.slice(nameStartIndex))
+
+    return { name, heroes, cards }
+}
+
+function cardDecoder(bytes) {
+    const bytesLength = bytes.length
+    var i = 0
+    var previousId = 0
+
+    function readVar(baseValue, baseBits) {
+        var result = 0
+        if (baseBits !== 0) {
+            let continueBit = 1 << baseBits
+            result = baseValue & (continueBit - 1)
+            if ((baseValue & continueBit) === 0) return result
+        }
+
+        var currentShift = baseBits
+        var currentByte
+        do {
+            if (i >= bytesLength) throw "invalid deck code"
+            currentByte = bytes[i++]
+            result |= ((currentByte & 127) << currentShift)
+            currentShift += 7
+        } while ((currentByte & 128) > 0)
+
+        return result
+    }
+
+    function readCard(nName = "n") {
+        if (i >= bytesLength) throw "invalid deck code"
+        const header = bytes[i++]
+        const id = previousId + readVar(header, 5)
+        previousId = id
+        var n = (header >>> 6)
+        if (n === 3) {
+            n = readVar(0, 0) // n is higher than 3 and is encoded separately
+        } else {
+            n += 1 // adding 1 since zero values are not encoded here
+        }
+
+        return { id, [nName]: n }
+    }
+
+    return {
+        readVar,
+        readCard,
+        hasNext: () => i < bytesLength,
+        resetPreviousId: () => previousId = 0
+    }
+}
+
+function computeChecksum(bytes) {
+    return 0xFF & bytes.reduce((a, b) => a + b, 0)
+}
diff --git a/javascript/package-lock.json b/javascript/package-lock.json
new file mode 100644
index 0000000..b7b380f
--- /dev/null
+++ b/javascript/package-lock.json
@@ -0,0 +1,201 @@
+{
+  "name": "artifact-deck-code",
+  "version": "0.0.1",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "balanced-match": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/balanced-match/-/balanced-match-1.0.0.tgz",
+      "integrity": "sha1-ibTRmasr7kneFk6gK4nORi1xt2c=",
+      "dev": true
+    },
+    "base64-js": {
+      "version": "1.3.0",
+      "resolved": "https://registry.npmjs.org/base64-js/-/base64-js-1.3.0.tgz",
+      "integrity": "sha512-ccav/yGvoa80BQDljCxsmmQ3Xvx60/UpBIij5QN21W3wBi/hhIC9OoO+KLpu9IJTS9j4DRVJ3aDDF9cMSoa2lw=="
+    },
+    "brace-expansion": {
+      "version": "1.1.11",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-1.1.11.tgz",
+      "integrity": "sha512-iCuPHDFgrHX7H2vEI/5xpz07zSHB00TpugqhmYtVmMO6518mCuRMoOYFldEBl0g187ufozdaHgWKcYFb61qGiA==",
+      "dev": true,
+      "requires": {
+        "balanced-match": "^1.0.0",
+        "concat-map": "0.0.1"
+      }
+    },
+    "browser-stdout": {
+      "version": "1.3.1",
+      "resolved": "https://registry.npmjs.org/browser-stdout/-/browser-stdout-1.3.1.tgz",
+      "integrity": "sha512-qhAVI1+Av2X7qelOfAIYwXONood6XlZE/fXaBSmW/T5SzLAmCgzi+eiWE7fUvbHaeNBQH13UftjpXxsfLkMpgw==",
+      "dev": true
+    },
+    "commander": {
+      "version": "2.15.1",
+      "resolved": "http://registry.npmjs.org/commander/-/commander-2.15.1.tgz",
+      "integrity": "sha512-VlfT9F3V0v+jr4yxPc5gg9s62/fIVWsd2Bk2iD435um1NlGMYdVCq+MjcXnhYq2icNOizHr1kK+5TI6H0Hy0ag==",
+      "dev": true
+    },
+    "concat-map": {
+      "version": "0.0.1",
+      "resolved": "https://registry.npmjs.org/concat-map/-/concat-map-0.0.1.tgz",
+      "integrity": "sha1-2Klr13/Wjfd5OnMDajug1UBdR3s=",
+      "dev": true
+    },
+    "debug": {
+      "version": "3.1.0",
+      "resolved": "https://registry.npmjs.org/debug/-/debug-3.1.0.tgz",
+      "integrity": "sha512-OX8XqP7/1a9cqkxYw2yXss15f26NKWBpDXQd0/uK/KPqdQhxbPa994hnzjcE2VqQpDslf55723cKPUOGSmMY3g==",
+      "dev": true,
+      "requires": {
+        "ms": "2.0.0"
+      }
+    },
+    "diff": {
+      "version": "3.5.0",
+      "resolved": "https://registry.npmjs.org/diff/-/diff-3.5.0.tgz",
+      "integrity": "sha512-A46qtFgd+g7pDZinpnwiRJtxbC1hpgf0uzP3iG89scHk0AUC7A1TGxf5OiiOUv/JMZR8GOt8hL900hV0bOy5xA==",
+      "dev": true
+    },
+    "escape-string-regexp": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz",
+      "integrity": "sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=",
+      "dev": true
+    },
+    "fs.realpath": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
+      "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8=",
+      "dev": true
+    },
+    "glob": {
+      "version": "7.1.2",
+      "resolved": "https://registry.npmjs.org/glob/-/glob-7.1.2.tgz",
+      "integrity": "sha512-MJTUg1kjuLeQCJ+ccE4Vpa6kKVXkPYJ2mOCQyUuKLcLQsdrMCpBPUi8qVE6+YuaJkozeA9NusTAw3hLr8Xe5EQ==",
+      "dev": true,
+      "requires": {
+        "fs.realpath": "^1.0.0",
+        "inflight": "^1.0.4",
+        "inherits": "2",
+        "minimatch": "^3.0.4",
+        "once": "^1.3.0",
+        "path-is-absolute": "^1.0.0"
+      }
+    },
+    "growl": {
+      "version": "1.10.5",
+      "resolved": "https://registry.npmjs.org/growl/-/growl-1.10.5.tgz",
+      "integrity": "sha512-qBr4OuELkhPenW6goKVXiv47US3clb3/IbuWF9KNKEijAy9oeHxU9IgzjvJhHkUzhaj7rOUD7+YGWqUjLp5oSA==",
+      "dev": true
+    },
+    "has-flag": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/has-flag/-/has-flag-3.0.0.tgz",
+      "integrity": "sha1-tdRU3CGZriJWmfNGfloH87lVuv0=",
+      "dev": true
+    },
+    "he": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/he/-/he-1.1.1.tgz",
+      "integrity": "sha1-k0EP0hsAlzUVH4howvJx80J+I/0=",
+      "dev": true
+    },
+    "inflight": {
+      "version": "1.0.6",
+      "resolved": "https://registry.npmjs.org/inflight/-/inflight-1.0.6.tgz",
+      "integrity": "sha1-Sb1jMdfQLQwJvJEKEHW6gWW1bfk=",
+      "dev": true,
+      "requires": {
+        "once": "^1.3.0",
+        "wrappy": "1"
+      }
+    },
+    "inherits": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.3.tgz",
+      "integrity": "sha1-Yzwsg+PaQqUC9SRmAiSA9CCCYd4=",
+      "dev": true
+    },
+    "minimatch": {
+      "version": "3.0.4",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-3.0.4.tgz",
+      "integrity": "sha512-yJHVQEhyqPLUTgt9B83PXu6W3rx4MvvHvSUvToogpwoGDOUQ+yDrR0HRot+yOCdCO7u4hX3pWft6kWBBcqh0UA==",
+      "dev": true,
+      "requires": {
+        "brace-expansion": "^1.1.7"
+      }
+    },
+    "minimist": {
+      "version": "0.0.8",
+      "resolved": "http://registry.npmjs.org/minimist/-/minimist-0.0.8.tgz",
+      "integrity": "sha1-hX/Kv8M5fSYluCKCYuhqp6ARsF0=",
+      "dev": true
+    },
+    "mkdirp": {
+      "version": "0.5.1",
+      "resolved": "http://registry.npmjs.org/mkdirp/-/mkdirp-0.5.1.tgz",
+      "integrity": "sha1-MAV0OOrGz3+MR2fzhkjWaX11yQM=",
+      "dev": true,
+      "requires": {
+        "minimist": "0.0.8"
+      }
+    },
+    "mocha": {
+      "version": "5.2.0",
+      "resolved": "https://registry.npmjs.org/mocha/-/mocha-5.2.0.tgz",
+      "integrity": "sha512-2IUgKDhc3J7Uug+FxMXuqIyYzH7gJjXECKe/w43IGgQHTSj3InJi+yAA7T24L9bQMRKiUEHxEX37G5JpVUGLcQ==",
+      "dev": true,
+      "requires": {
+        "browser-stdout": "1.3.1",
+        "commander": "2.15.1",
+        "debug": "3.1.0",
+        "diff": "3.5.0",
+        "escape-string-regexp": "1.0.5",
+        "glob": "7.1.2",
+        "growl": "1.10.5",
+        "he": "1.1.1",
+        "minimatch": "3.0.4",
+        "mkdirp": "0.5.1",
+        "supports-color": "5.4.0"
+      }
+    },
+    "ms": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/ms/-/ms-2.0.0.tgz",
+      "integrity": "sha1-VgiurfwAvmwpAd9fmGF4jeDVl8g=",
+      "dev": true
+    },
+    "once": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/once/-/once-1.4.0.tgz",
+      "integrity": "sha1-WDsap3WWHUsROsF9nFC6753Xa9E=",
+      "dev": true,
+      "requires": {
+        "wrappy": "1"
+      }
+    },
+    "path-is-absolute": {
+      "version": "1.0.1",
+      "resolved": "http://registry.npmjs.org/path-is-absolute/-/path-is-absolute-1.0.1.tgz",
+      "integrity": "sha1-F0uSaHNVNP+8es5r9TpanhtcX18=",
+      "dev": true
+    },
+    "supports-color": {
+      "version": "5.4.0",
+      "resolved": "https://registry.npmjs.org/supports-color/-/supports-color-5.4.0.tgz",
+      "integrity": "sha512-zjaXglF5nnWpsq470jSv6P9DwPvgLkuapYmfDm3JWOm0vkNTVF2tI4UrN2r6jH1qM/uc/WtxYY1hYoA2dOKj5w==",
+      "dev": true,
+      "requires": {
+        "has-flag": "^3.0.0"
+      }
+    },
+    "wrappy": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
+      "integrity": "sha1-tSQ9jz7BqjXxNkYFvA0QNuMKtp8=",
+      "dev": true
+    }
+  }
+}
diff --git a/javascript/package.json b/javascript/package.json
new file mode 100644
index 0000000..8e49698
--- /dev/null
+++ b/javascript/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "artifact-deck-code",
+  "version": "0.0.1",
+  "description": "Module for encoding/decoding Artifact deck codes.",
+  "author": "NorthFury",
+  "license": "BSD-3-Clause",
+  "main": "index.js",
+  "scripts": {
+    "test": "mocha --harmony test"
+  },
+  "dependencies": {
+    "base64-js": "1.3.0"
+  },
+  "devDependencies": {
+    "mocha": "5.2.0"
+  }
+}
diff --git a/javascript/test/deck.json b/javascript/test/deck.json
new file mode 100644
index 0000000..f34944b
--- /dev/null
+++ b/javascript/test/deck.json
@@ -0,0 +1,87 @@
+{
+  "name": "Green/Black Example",
+  "heroes": [
+    {
+      "id": 4005,
+      "turn": 2
+    },
+    {
+      "id": 10014,
+      "turn": 1
+    },
+    {
+      "id": 10017,
+      "turn": 3
+    },
+    {
+      "id": 10026,
+      "turn": 1
+    },
+    {
+      "id": 10047,
+      "turn": 1
+    }
+  ],
+  "cards": [
+    {
+      "id": 3000,
+      "count": 2
+    },
+    {
+      "id": 3001,
+      "count": 1
+    },
+    {
+      "id": 10091,
+      "count": 3
+    },
+    {
+      "id": 10102,
+      "count": 3
+    },
+    {
+      "id": 10128,
+      "count": 3
+    },
+    {
+      "id": 10165,
+      "count": 3
+    },
+    {
+      "id": 10168,
+      "count": 3
+    },
+    {
+      "id": 10169,
+      "count": 3
+    },
+    {
+      "id": 10185,
+      "count": 3
+    },
+    {
+      "id": 10223,
+      "count": 1
+    },
+    {
+      "id": 10234,
+      "count": 3
+    },
+    {
+      "id": 10260,
+      "count": 1
+    },
+    {
+      "id": 10263,
+      "count": 1
+    },
+    {
+      "id": 10322,
+      "count": 3
+    },
+    {
+      "id": 10354,
+      "count": 3
+    }
+  ]
+}
\ No newline at end of file
diff --git a/javascript/test/index.js b/javascript/test/index.js
new file mode 100644
index 0000000..7a87442
--- /dev/null
+++ b/javascript/test/index.js
@@ -0,0 +1,65 @@
+'use strict'
+
+const assert = require('assert')
+const { parseDeck, encodeDeck } = require('../')
+
+const deck = require('./deck.json')
+const DECK_CODE = "ADCJWkTZX05uwGDCRV4XQGy3QGLmqUBg4GQJgGLGgO7AaABR3JlZW4vQmxhY2sgRXhhbXBsZQ__"
+
+describe('encodeDeck', function () {
+    it('should encode a deck', function () {
+        const result = encodeDeck(deck)
+        assert.equal(result, DECK_CODE)
+    })
+
+    it('should encode a deck with unordered cards and heroes', function () {
+        const newDeck = {
+            name: deck.name,
+            heroes: deck.heroes.slice(0).reverse(),
+            cards: deck.cards.slice(0).reverse()
+        }
+        const result = encodeDeck(deck)
+        assert.equal(result, DECK_CODE)
+    })
+})
+
+describe('parseDeck', function () {
+    it('should decode v2 deck code', function () {
+        const result = parseDeck(DECK_CODE)
+        assert.equal(result.name, deck.name)
+        assert.equal(areTheCardArraysEqual(result.heroes, deck.heroes), true)
+        assert.equal(areTheCardArraysEqual(result.cards, deck.cards), true)
+    })
+
+    it('should decode v1 deck code', function () {
+        const result = parseDeck("ADCFWllfTm7AYMJFXhdAbLdAYuapQGDgZAmAYsaA7sBoAE_")
+        assert.equal(result.name, "")
+        assert.equal(areTheCardArraysEqual(result.heroes, deck.heroes), true)
+        assert.equal(areTheCardArraysEqual(result.cards, deck.cards), true)
+    })
+})
+
+
+function areTheCardArraysEqual(a, b) {
+    if (a.length !== b.length) return false
+    a.sort((a, b) => a.id - b.id)
+    b.sort((a, b) => a.id - b.id)
+
+    for (let i = 0, n = a.length; i < n; i++) {
+        if (!areTheObjectsEqual(a[i], b[i])) return false
+    }
+
+    return true
+}
+
+function areTheObjectsEqual(a, b) {
+    const ak = Object.keys(a)
+    const bk = Object.keys(b)
+    if (ak.length !== bk.length) return false
+
+    for (let i = 0, n = ak.length; i < n; i++) {
+        if (a[ak[i]] !== b[bk[i]]) return false
+    }
+
+    return true
+}