diff --git a/.eslintignore b/.eslintignore
new file mode 100644
index 0000000..58a4708
--- /dev/null
+++ b/.eslintignore
@@ -0,0 +1,3 @@
+/node_modules
+/.nyc_output
+/coverage
diff --git a/.eslintrc b/.eslintrc
new file mode 100644
index 0000000..c893eab
--- /dev/null
+++ b/.eslintrc
@@ -0,0 +1,3 @@
+{
+    "extends": ["scratch", "scratch/node"]
+}
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..daf35a7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,11 @@
+## OSX
+.DS_Store
+
+## NPM
+/node_modules
+npm-*
+package-lock.json
+
+## Code Coverage
+.nyc_output/
+coverage/
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..afb20c5
--- /dev/null
+++ b/README.md
@@ -0,0 +1,45 @@
+## scratch-analysis
+#### Analysis tool for summarizing the structure, composition, and complexity of [Scratch](https://scratch.mit.edu) programs.
+
+## Getting Started
+```bash
+npm install scratch-analysis
+```
+
+```js
+const analysis = require('scratch-analysis');
+analysis(buffer, function (err, result) {
+    // handle any validation errors and ...
+    // do something interesting with the results!
+});
+```
+
+## Analysis Modules
+### General
+The `scratch-analysis` module will return an object containing high-level summary information about the project:
+
+| Key               | Attributes                                               |
+| ----------------- | -------------------------------------------------------- |
+| `scripts`         | `count`                                                  |
+| `blocks`          | `count`, `unique`, `list`, `frequency`                   |
+| `sprites`         | `count`                                                  |
+| `variables`       | `count`                                                  |
+| `lists`           | `count`                                                  |
+| `costumes`        | `count`, `list`, `hash`                                  |
+| `sounds`          | `count`, `list`, `hash`                                  |
+| `extensions`      | `count`, `list`                                          |
+| `comments`        | `count`                                                  |
+
+### Concepts
+**Coming Soon**
+
+### Complexity
+**Coming Soon**
+
+### Classification
+**Coming Soon**
+
+## References
+### New Frameworks for Studying and Assessing the Development of Computational Thinking
+Author(s): Karen Brennan, Mitchel Resnick
+PDF: [Download](https://web.media.mit.edu/~kbrennan/files/Brennan_Resnick_AERA2012_CT.pdf)
diff --git a/lib/index.js b/lib/index.js
new file mode 100644
index 0000000..8a26121
--- /dev/null
+++ b/lib/index.js
@@ -0,0 +1,23 @@
+const parser = require('scratch-parser');
+
+const sb2 = require('./sb2');
+const sb3 = require('./sb3');
+
+module.exports = function (buffer, callback) {
+    parser(buffer, false, (err, result) => {
+        if (err) return callback(err);
+
+        // Extract only the project object from the parser results
+        const project = result[0];
+
+        // Push project object to the appropriate analysis handler
+        switch (project.projectVersion) {
+        case 2:
+            sb2(project, callback);
+            break;
+        case 3:
+            sb3(project, callback);
+            break;
+        }
+    });
+};
diff --git a/lib/sb2.js b/lib/sb2.js
new file mode 100644
index 0000000..4831957
--- /dev/null
+++ b/lib/sb2.js
@@ -0,0 +1,185 @@
+const utility = require('./utility');
+
+/**
+ * Returns an array of items matching the specified attribute.
+ * @param  {object} project   Project object (SB2 format)
+ * @param  {string} attribute Attribute to extract and flatten
+ * @return {array}            Array of specified attribute
+ */
+const flatten = function (project, attribute) {
+    // Storage object
+    let result = [];
+
+    // If attribute exists at the top level of the project, append it
+    if (typeof project[attribute] !== 'undefined') {
+        result = project[attribute];
+    }
+
+    // Iterate over child elements and append to result array
+    for (let i in project.children) {
+        const child = project.children[i];
+        if (typeof child[attribute] !== 'undefined') {
+            result = result.concat(child[attribute]);
+        }
+    }
+
+    return result;
+};
+
+/**
+ * Extract summary information from a specific project attribute. Will attempt
+ * to concatinate all children when generating summary.
+ * @param  {object} project   Project object (SB2 format)
+ * @param  {string} attribute Attribute key
+ * @param  {string} id        "id" key
+ * @param  {string} hash      "hash" key
+ * @return {object}           Summary information
+ */
+const extract = function (project, attribute, id, hash) {
+    // Create storage objects and flatten project
+    let idList = null;
+    let hashList = null;
+    let elements = flatten(project, attribute);
+
+    // Extract ids if specified
+    if (typeof id !== 'undefined') {
+        idList = [];
+        for (var x in elements) {
+            idList.push(elements[x][id]);
+        }
+    }
+
+    // Extract hashes if specified
+    if (typeof hash !== 'undefined') {
+        hashList = [];
+        for (var y in elements) {
+            hashList.push(elements[y][hash]);
+        }
+    }
+
+    // Build result and return
+    var result = {
+        count: elements.length
+    };
+    if (idList !== null) result.id = idList;
+    if (hashList !== null) result.hash = hashList;
+
+    return result;
+};
+
+/**
+ * Extract number of sprites from a project object. Will attempt to ignore
+ * "children" which are not sprites.
+ * @param  {object} input Project object (SB2 format)
+ * @return {object}       Sprite information
+ */
+const sprites = function (input) {
+    let result = 0;
+
+    for (let i in input.children) {
+        if (input.children[i].hasOwnProperty('spriteInfo')) result++;
+    }
+
+    return {count: result};
+};
+
+/**
+ * Extracts all blocks and generates a frequency count.
+ * @param  {object} project Project object (SB2 format)
+ * @return {object}         Block information
+ */
+const blocks = function (project) {
+    // Storage objects
+    const result = [];
+
+    /**
+     * Walk scripts array(s) and build block list.
+     * @param  {array} stack Stack of blocks
+     * @return {void}
+     */
+    const walk = function (stack) {
+        for (let i in stack) {
+            // Skip if item is not array
+            if (!Array.isArray(stack[i])) continue;
+
+            // Recurse if first item is not a string
+            if (typeof stack[i][0] !== 'string') {
+                walk(stack[i]);
+                continue;
+            }
+
+            // Add to block list
+            result.push(stack[i][0]);
+
+            // Don't pull in params from procedures
+            if (stack[i][0] === 'procDef') continue;
+
+            // Move to next item and walk
+            walk(stack[i].slice(1));
+        }
+    };
+    walk(flatten(project, 'scripts'));
+
+    // Generate frequency count
+    const freq = utility.frequency(result);
+
+    // Build result and return
+    return {
+        count: result.length,
+        unique: Object.keys(freq).length,
+        id: result,
+        frequency: freq
+    };
+};
+
+/**
+ * Extracts extension information.
+ * @param  {object} project Project object (SB2 format)
+ * @return {object}         Extension information
+ */
+const extensions = function (project) {
+    const result = {count: 0, id: []};
+    const ext = project.info.savedExtensions;
+
+    // Check to ensure project includes any extensions
+    if (typeof ext === 'undefined') return result;
+
+    // Iterate over extensions and build list
+    for (let i in ext) {
+        result.id.push(ext[i].extensionName);
+    }
+
+    // Count and return
+    result.count = result.id.length;
+    return result;
+};
+
+/**
+ * Analyzes a project and returns summary information about the project.
+ * @param  {object}   project  Project object (SB2 format)
+ * @param  {Function} callback Callback function
+ * @return {void}
+ */
+module.exports = function (project, callback) {
+    // Create metadata object
+    const meta = {
+        scripts: extract(project, 'scripts'),
+        variables: extract(project, 'variables', 'name'),
+        lists: extract(project, 'lists', 'listName'),
+        comments: extract(project, 'scriptComments'),
+        sounds: extract(project, 'sounds', 'soundName', 'md5'),
+        costumes: extract(project, 'costumes', 'costumeName', 'baseLayerMD5')
+    };
+
+    // Sprites
+    meta.sprites = sprites(project);
+
+    // Blocks
+    meta.blocks = blocks(project);
+
+    // Extensions
+    meta.extensions = extensions(project);
+
+    // Return all metadata
+    return callback(null, meta);
+};
diff --git a/lib/sb3.js b/lib/sb3.js
new file mode 100644
index 0000000..b9c910c
--- /dev/null
+++ b/lib/sb3.js
@@ -0,0 +1,110 @@
+const utility = require('./utility');
+
+const scripts = function (targets) {
+    // Storage objects
+    let occurrences = 0;
+
+    // Iterate over all blocks in each target, and look for "top level" blocks
+    for (let t in targets) {
+        for (let b in targets[t].blocks) {
+            if (targets[t].blocks[b].topLevel) occurrences++;
+        }
+    }
+
+    return {
+        count: occurrences
+    };
+};
+
+const variables = function (targets, attribute) {
+    // Storage objects
+    let occurrences = 0;
+    let idList = [];
+
+    for (let t in targets) {
+        for (let a in targets[t][attribute]) {
+            const variable = targets[t][attribute][a];
+            occurrences++;
+            idList.push(variable[0]);
+        }
+    }
+
+    return {
+        count: occurrences,
+        id: idList
+    };
+};
+
+// Iterate over targets, extract attribute, and aggregate results
+const extract = function (targets, attribute, id, hash) {
+    // Storage objects
+    let occurrences = 0;
+    let idList = [];
+    let hashList = [];
+
+    for (let t in targets) {
+        for (let a in targets[t][attribute]) {
+            const asset = targets[t][attribute][a];
+            occurrences++;
+            if (typeof id !== 'undefined') idList.push(asset[id]);
+            if (typeof hash !== 'undefined') hashList.push(asset[hash]);
+        }
+    }
+
+    const result = {count: occurrences};
+    if (typeof id !== 'undefined') result.id = idList;
+    if (typeof hash !== 'undefined') result.hash = hashList;
+    return result;
+};
+
+const sprites = function (targets) {
+    return {
+        count: targets.length - 1
+    };
+};
+
+const blocks = function (targets) {
+    // Storage object
+    let result = [];
+
+    for (let t in targets) {
+        for (let a in targets[t].blocks) {
+            const block = targets[t].blocks[a];
+            if (!block.shadow) result.push(block.opcode);
+        }
+    }
+
+    // Calculate block frequency
+    const freq = utility.frequency(result);
+
+    // Return summary
+    return {
+        count: result.length,
+        unique: Object.keys(freq).length,
+        id: result,
+        frequency: freq
+    };
+};
+
+const extensions = function (list) {
+    return {
+        count: list.length,
+        id: list
+    };
+};
+
+module.exports = function (project, callback) {
+    const meta = {
+        scripts: scripts(project.targets),
+        variables: variables(project.targets, 'variables'),
+        lists: variables(project.targets, 'lists'),
+        comments: extract(project.targets, 'comments'),
+        sounds: extract(project.targets, 'sounds', 'name', 'md5ext'),
+        costumes: extract(project.targets, 'costumes', 'name', 'md5ext'),
+        sprites: sprites(project.targets),
+        blocks: blocks(project.targets),
+        extensions: extensions(project.extensions)
+    };
+
+    callback(null, meta);
+};
diff --git a/lib/utility.js b/lib/utility.js
new file mode 100644
index 0000000..cb83509
--- /dev/null
+++ b/lib/utility.js
@@ -0,0 +1,23 @@
+/**
+ * Utility methods for costructing Scratch project summaries.
+ */
+class Utility {
+    /**
+     * Tallies term frequency from an array of strings.
+     * @param  {array} input Array of strings
+     * @return {object}      Frequency information
+     */
+    static frequency (input) {
+        const result = Object.create(null);
+
+        for (let i in input) {
+            var term = input[i];
+            if (typeof result[term] === 'undefined') result[term] = 0;
+            result[term]++;
+        }
+
+        return result;
+    }
+}
+
+module.exports = Utility;
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..5308d51
--- /dev/null
+++ b/package.json
@@ -0,0 +1,28 @@
+{
+  "name": "scratch-analysis",
+  "version": "1.0.0",
+  "description": "Analysis tool for summarizing the structure, composition, and complexity of Scratch programs.",
+  "main": "lib/index.js",
+  "directories": {
+    "lib": "lib",
+    "test": "test"
+  },
+  "scripts": {
+    "test": "npm run test:lint && npm run test:unit && npm run test:integration",
+    "test:lint": "eslint .",
+    "test:unit": "tap test/unit/*.js",
+    "test:integration": "tap test/integration/*.js",
+    "test:coverage": "tap test/{unit,integration}/*.js --coverage --coverage-report=lcov"
+  },
+  "author": "Scratch Foundation",
+  "license": "BSD-3-Clause",
+  "dependencies": {
+    "scratch-parser": "4.3.2"
+  },
+  "devDependencies": {
+    "babel-eslint": "^10.0.1",
+    "eslint": "^5.10.0",
+    "eslint-config-scratch": "^5.0.0",
+    "tap": "^12.1.1"
+  }
+}
diff --git a/test/fixtures/invalid/garbage.jpg b/test/fixtures/invalid/garbage.jpg
new file mode 100644
index 0000000..0cde843
Binary files /dev/null and b/test/fixtures/invalid/garbage.jpg differ
diff --git a/test/fixtures/sb2/complex.sb2 b/test/fixtures/sb2/complex.sb2
new file mode 100644
index 0000000..43d16c3
Binary files /dev/null and b/test/fixtures/sb2/complex.sb2 differ
diff --git a/test/fixtures/sb2/default.json b/test/fixtures/sb2/default.json
new file mode 100644
index 0000000..af478a4
--- /dev/null
+++ b/test/fixtures/sb2/default.json
@@ -0,0 +1,71 @@
+{
+   "objName": "Stage",
+   "sounds": [{
+           "soundName": "pop",
+           "soundID": -1,
+           "md5": "83a9787d4cb6f3b7632b4ddfebf74367.wav",
+           "sampleCount": 258,
+           "rate": 11025,
+           "format": ""
+       }],
+   "costumes": [{
+           "costumeName": "backdrop1",
+           "baseLayerID": -1,
+           "baseLayerMD5": "739b5e2a2435f6e1ec2993791b423146.png",
+           "bitmapResolution": 1,
+           "rotationCenterX": 240,
+           "rotationCenterY": 180
+       }],
+   "currentCostumeIndex": 0,
+   "penLayerMD5": "5c81a336fab8be57adc039a8a2b33ca9.png",
+   "penLayerID": -1,
+   "tempoBPM": 60,
+   "videoAlpha": 0.5,
+   "children": [{
+           "objName": "Sprite1",
+           "sounds": [{
+                   "soundName": "meow",
+                   "soundID": -1,
+                   "md5": "83c36d806dc92327b9e7049a565c6bff.wav",
+                   "sampleCount": 18688,
+                   "rate": 22050,
+                   "format": ""
+               }],
+           "costumes": [{
+                   "costumeName": "costume1",
+                   "baseLayerID": -1,
+                   "baseLayerMD5": "09dc888b0b7df19f70d81588ae73420e.svg",
+                   "bitmapResolution": 1,
+                   "rotationCenterX": 47,
+                   "rotationCenterY": 55
+               },
+               {
+                   "costumeName": "costume2",
+                   "baseLayerID": -1,
+                   "baseLayerMD5": "3696356a03a8d938318876a593572843.svg",
+                   "bitmapResolution": 1,
+                   "rotationCenterX": 47,
+                   "rotationCenterY": 55
+               }],
+           "currentCostumeIndex": 0,
+           "scratchX": 0,
+           "scratchY": 0,
+           "scale": 1,
+           "direction": 90,
+           "rotationStyle": "normal",
+           "isDraggable": false,
+           "indexInLibrary": 1,
+           "visible": true,
+           "spriteInfo": {
+           }
+       }],
+   "info": {
+       "videoOn": false,
+       "userAgent": "Mozilla\/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit\/537.36 (KHTML, like Gecko) Chrome\/50.0.2661.102 Safari\/537.36",
+       "swfVersion": "v446",
+       "scriptCount": 0,
+       "spriteCount": 1,
+       "hasCloudData": false,
+       "flashVersion": "MAC 21,0,0,242"
+   }
+}
diff --git a/test/fixtures/sb2/default.sb2 b/test/fixtures/sb2/default.sb2
new file mode 100644
index 0000000..fe7426f
Binary files /dev/null and b/test/fixtures/sb2/default.sb2 differ
diff --git a/test/fixtures/sb3/complex.sb3 b/test/fixtures/sb3/complex.sb3
new file mode 100644
index 0000000..b4a300b
Binary files /dev/null and b/test/fixtures/sb3/complex.sb3 differ
diff --git a/test/fixtures/sb3/default.json b/test/fixtures/sb3/default.json
new file mode 100644
index 0000000..3235973
--- /dev/null
+++ b/test/fixtures/sb3/default.json
@@ -0,0 +1,103 @@
+{
+  "targets": [
+    {
+      "isStage": true,
+      "name": "Stage",
+      "variables": {
+        "`jEk@4|i[#Fk?(8x)AV.-my variable": [
+          "my variable",
+          0
+        ]
+      },
+      "lists": {},
+      "broadcasts": {},
+      "blocks": {},
+      "comments": {},
+      "currentCostume": 0,
+      "costumes": [
+        {
+          "assetId": "cd21514d0531fdffb22204e0ec5ed84a",
+          "name": "backdrop1",
+          "md5ext": "cd21514d0531fdffb22204e0ec5ed84a.svg",
+          "dataFormat": "svg",
+          "rotationCenterX": 240,
+          "rotationCenterY": 180
+        }
+      ],
+      "sounds": [
+        {
+          "assetId": "83a9787d4cb6f3b7632b4ddfebf74367",
+          "name": "pop",
+          "dataFormat": "wav",
+          "format": "",
+          "rate": 44100,
+          "sampleCount": 1032,
+          "md5ext": "83a9787d4cb6f3b7632b4ddfebf74367.wav"
+        }
+      ],
+      "volume": 100,
+      "layerOrder": 0,
+      "tempo": 60,
+      "videoTransparency": 50,
+      "videoState": "on",
+      "textToSpeechLanguage": null
+    },
+    {
+      "isStage": false,
+      "name": "Sprite1",
+      "variables": {},
+      "lists": {},
+      "broadcasts": {},
+      "blocks": {},
+      "comments": {},
+      "currentCostume": 0,
+      "costumes": [
+        {
+          "assetId": "b7853f557e4426412e64bb3da6531a99",
+          "name": "costume1",
+          "bitmapResolution": 1,
+          "md5ext": "b7853f557e4426412e64bb3da6531a99.svg",
+          "dataFormat": "svg",
+          "rotationCenterX": 48,
+          "rotationCenterY": 50
+        },
+        {
+          "assetId": "e6ddc55a6ddd9cc9d84fe0b4c21e016f",
+          "name": "costume2",
+          "bitmapResolution": 1,
+          "md5ext": "e6ddc55a6ddd9cc9d84fe0b4c21e016f.svg",
+          "dataFormat": "svg",
+          "rotationCenterX": 46,
+          "rotationCenterY": 53
+        }
+      ],
+      "sounds": [
+        {
+          "assetId": "83c36d806dc92327b9e7049a565c6bff",
+          "name": "Meow",
+          "dataFormat": "wav",
+          "format": "",
+          "rate": 44100,
+          "sampleCount": 37376,
+          "md5ext": "83c36d806dc92327b9e7049a565c6bff.wav"
+        }
+      ],
+      "volume": 100,
+      "layerOrder": 1,
+      "visible": true,
+      "x": 0,
+      "y": 0,
+      "size": 100,
+      "direction": 90,
+      "draggable": false,
+      "rotationStyle": "all around"
+    }
+  ],
+  "monitors": [],
+  "extensions": [],
+  "meta": {
+    "semver": "3.0.0",
+    "vm": "0.2.0-prerelease.20181217191056",
+    "agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36"
+  }
+}
diff --git a/test/fixtures/sb3/default.sb3 b/test/fixtures/sb3/default.sb3
new file mode 100644
index 0000000..455acd3
Binary files /dev/null and b/test/fixtures/sb3/default.sb3 differ
diff --git a/test/unit/error.js b/test/unit/error.js
new file mode 100644
index 0000000..32a6ec7
--- /dev/null
+++ b/test/unit/error.js
@@ -0,0 +1,24 @@
+const fs = require('fs');
+const path = require('path');
+const test = require('tap').test;
+const analysis = require('../../lib/index');
+
+const invalidBinary = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/invalid/garbage.jpg')
+);
+
+test('invalid object', t => {
+    analysis('{}', (err, result) => {
+        t.type(err, 'object');
+        t.type(result, 'undefined');
+        t.end();
+    });
+});
+
+test('invalid binary', t => {
+    analysis(invalidBinary, (err, result) => {
+        t.type(err, 'string');
+        t.type(result, 'undefined');
+        t.end();
+    });
+});
diff --git a/test/unit/sb2.js b/test/unit/sb2.js
new file mode 100644
index 0000000..261211c
--- /dev/null
+++ b/test/unit/sb2.js
@@ -0,0 +1,256 @@
+const fs = require('fs');
+const path = require('path');
+const test = require('tap').test;
+const analysis = require('../../lib/index');
+
+const defaultObject = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb2/default.json')
+);
+const defaultBinary = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb2/default.sb2')
+);
+const complexBinary = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb2/complex.sb2')
+);
+
+test('defalt (object)', t => {
+    analysis(defaultObject, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 0);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 0);
+        t.deepEqual(result.variables.id, []);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 0);
+        t.deepEqual(result.lists.id, []);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            '739b5e2a2435f6e1ec2993791b423146.png',
+            '09dc888b0b7df19f70d81588ae73420e.svg',
+            '3696356a03a8d938318876a593572843.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 0);
+        t.equal(result.blocks.unique, 0);
+        t.deepEqual(result.blocks.id, []);
+        t.deepEqual(result.blocks.frequency, {});
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 0);
+        t.deepEqual(result.extensions.id, []);
+
+        t.end();
+    });
+});
+
+test('defalt (binary)', t => {
+    analysis(defaultBinary, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 0);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 0);
+        t.deepEqual(result.variables.id, []);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 0);
+        t.deepEqual(result.lists.id, []);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            '739b5e2a2435f6e1ec2993791b423146.png',
+            'f9a1c175dbe2e5dee472858dd30d16bb.svg',
+            '6e8bd9ae68fdb02b7e1e3df656a75635.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 0);
+        t.equal(result.blocks.unique, 0);
+        t.deepEqual(result.blocks.id, []);
+        t.deepEqual(result.blocks.frequency, {});
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 0);
+        t.deepEqual(result.extensions.id, []);
+
+        t.end();
+    });
+});
+
+test('complex (binary)', t => {
+    analysis(complexBinary, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 6);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 2);
+        t.deepEqual(result.variables.id, [
+            'global',
+            'local'
+        ]);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 2);
+        t.deepEqual(result.lists.id, [
+            'globallist',
+            'locallist'
+        ]);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            '5b465b3b07d39019109d8dc6d6ee6593.svg',
+            'f9a1c175dbe2e5dee472858dd30d16bb.svg',
+            '6e8bd9ae68fdb02b7e1e3df656a75635.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 34);
+        t.equal(result.blocks.unique, 18);
+        t.deepEqual(result.blocks.id, [
+            'whenGreenFlag',
+            'doForever',
+            'changeGraphicEffect:by:',
+            'whenGreenFlag',
+            'deleteLine:ofList:',
+            'deleteLine:ofList:',
+            'doForever',
+            'forward:',
+            'turnRight:',
+            'randomFrom:to:',
+            'bounceOffEdge',
+            'whenGreenFlag',
+            'doForever',
+            'setGraphicEffect:to:',
+            'xpos',
+            'whenGreenFlag',
+            'doForever',
+            'call',
+            'randomFrom:to:',
+            'heading',
+            'randomFrom:to:',
+            'heading',
+            'procDef',
+            'setVar:to:',
+            'getParam',
+            'setVar:to:',
+            'getParam',
+            'append:toList:',
+            'getParam',
+            'append:toList:',
+            'getParam',
+            'LEGO WeDo 2.0\u001FwhenTilted',
+            'LEGO WeDo 2.0\u001FsetLED',
+            'randomFrom:to:'
+        ]);
+        t.deepEqual(result.blocks.frequency, {
+            'LEGO WeDo 2.0\u001FsetLED': 1,
+            'LEGO WeDo 2.0\u001FwhenTilted': 1,
+            'bounceOffEdge': 1,
+            'call': 1,
+            'changeGraphicEffect:by:': 1,
+            'doForever': 4,
+            'deleteLine:ofList:': 2,
+            'forward:': 1,
+            'getParam': 4,
+            'heading': 2,
+            'procDef': 1,
+            'append:toList:': 2,
+            'randomFrom:to:': 4,
+            'setGraphicEffect:to:': 1,
+            'setVar:to:': 2,
+            'turnRight:': 1,
+            'whenGreenFlag': 4,
+            'xpos': 1
+        });
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 1);
+        t.deepEqual(result.extensions.id, [
+            'LEGO WeDo 2.0'
+        ]);
+
+        t.end();
+    });
+});
diff --git a/test/unit/sb3.js b/test/unit/sb3.js
new file mode 100644
index 0000000..8edf126
--- /dev/null
+++ b/test/unit/sb3.js
@@ -0,0 +1,260 @@
+const fs = require('fs');
+const path = require('path');
+const test = require('tap').test;
+const analysis = require('../../lib/index');
+
+const defaultObject = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb3/default.json')
+);
+const defaultBinary = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb3/default.sb3')
+);
+const complexBinary = fs.readFileSync(
+    path.resolve(__dirname, '../fixtures/sb3/complex.sb3')
+);
+
+test('defalt (object)', t => {
+    analysis(defaultObject, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 0);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 1);
+        t.deepEqual(result.variables.id, [
+            'my variable'
+        ]);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 0);
+        t.deepEqual(result.lists.id, []);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'Meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            'cd21514d0531fdffb22204e0ec5ed84a.svg',
+            'b7853f557e4426412e64bb3da6531a99.svg',
+            'e6ddc55a6ddd9cc9d84fe0b4c21e016f.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 0);
+        t.equal(result.blocks.unique, 0);
+        t.deepEqual(result.blocks.id, []);
+        t.deepEqual(result.blocks.frequency, {});
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 0);
+        t.deepEqual(result.extensions.id, []);
+
+        t.end();
+    });
+});
+
+test('defalt (binary)', t => {
+    analysis(defaultBinary, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 0);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 1);
+        t.deepEqual(result.variables.id, [
+            'my variable'
+        ]);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 0);
+        t.deepEqual(result.lists.id, []);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'Meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            'cd21514d0531fdffb22204e0ec5ed84a.svg',
+            'b7853f557e4426412e64bb3da6531a99.svg',
+            'e6ddc55a6ddd9cc9d84fe0b4c21e016f.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 0);
+        t.equal(result.blocks.unique, 0);
+        t.deepEqual(result.blocks.id, []);
+        t.deepEqual(result.blocks.frequency, {});
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 0);
+        t.deepEqual(result.extensions.id, []);
+
+        t.end();
+    });
+});
+
+test('complex (binary)', t => {
+    analysis(complexBinary, (err, result) => {
+        t.true(typeof err === 'undefined' || err === null);
+        t.type(result, 'object');
+
+        t.type(result.scripts, 'object');
+        t.equal(result.scripts.count, 6);
+
+        t.type(result.variables, 'object');
+        t.equal(result.variables.count, 2);
+        t.deepEqual(result.variables.id, [
+            'global',
+            'local'
+        ]);
+
+        t.type(result.lists, 'object');
+        t.equal(result.lists.count, 2);
+        t.deepEqual(result.lists.id, [
+            'globallist',
+            'locallist'
+        ]);
+
+        t.type(result.comments, 'object');
+        t.equal(result.comments.count, 0);
+
+        t.type(result.sounds, 'object');
+        t.equal(result.sounds.count, 2);
+        t.deepEqual(result.sounds.id, [
+            'pop',
+            'meow'
+        ]);
+        t.deepEqual(result.sounds.hash, [
+            '83a9787d4cb6f3b7632b4ddfebf74367.wav',
+            '83c36d806dc92327b9e7049a565c6bff.wav'
+        ]);
+
+        t.type(result.costumes, 'object');
+        t.equal(result.costumes.count, 3);
+        t.deepEqual(result.costumes.id, [
+            'backdrop1',
+            'costume1',
+            'costume2'
+        ]);
+        t.deepEqual(result.costumes.hash, [
+            '7633d36de03d1df75808f581bbccc742.svg',
+            'e6bcb4046c157f60c9f5c3bb5f299fce.svg',
+            '64208764c777be25d34d813dc0b743c7.svg'
+        ]);
+
+        t.type(result.sprites, 'object');
+        t.equal(result.sprites.count, 1);
+
+        t.type(result.blocks, 'object');
+        t.equal(result.blocks.count, 34);
+        t.equal(result.blocks.unique, 18);
+        t.deepEqual(result.blocks.id, [
+            'event_whenflagclicked',
+            'control_forever',
+            'looks_changeeffectby',
+            'event_whenflagclicked',
+            'data_deleteoflist',
+            'data_deleteoflist',
+            'control_forever',
+            'motion_movesteps',
+            'motion_turnright',
+            'operator_random',
+            'motion_ifonedgebounce',
+            'event_whenflagclicked',
+            'control_forever',
+            'looks_seteffectto',
+            'motion_xposition',
+            'event_whenflagclicked',
+            'control_forever',
+            'procedures_call',
+            'operator_random',
+            'motion_direction',
+            'operator_random',
+            'motion_direction',
+            'procedures_definition',
+            'data_setvariableto',
+            'argument_reporter_string_number',
+            'data_setvariableto',
+            'argument_reporter_string_number',
+            'data_addtolist',
+            'argument_reporter_string_number',
+            'data_addtolist',
+            'argument_reporter_string_number',
+            'wedo2_whenTilted',
+            'wedo2_setLightHue',
+            'operator_random'
+        ]);
+        t.deepEqual(result.blocks.frequency, {
+            argument_reporter_string_number: 4,
+            control_forever: 4,
+            data_addtolist: 2,
+            data_deleteoflist: 2,
+            data_setvariableto: 2,
+            event_whenflagclicked: 4,
+            looks_changeeffectby: 1,
+            looks_seteffectto: 1,
+            motion_direction: 2,
+            motion_ifonedgebounce: 1,
+            motion_movesteps: 1,
+            motion_turnright: 1,
+            motion_xposition: 1,
+            operator_random: 4,
+            procedures_call: 1,
+            procedures_definition: 1,
+            wedo2_setLightHue: 1,
+            wedo2_whenTilted: 1
+        });
+
+        t.type(result.extensions, 'object');
+        t.equal(result.extensions.count, 1);
+        t.deepEqual(result.extensions.id, [
+            'wedo2'
+        ]);
+
+        t.end();
+    });
+});
diff --git a/test/unit/spec.js b/test/unit/spec.js
new file mode 100644
index 0000000..d9e1d0a
--- /dev/null
+++ b/test/unit/spec.js
@@ -0,0 +1,7 @@
+const test = require('tap').test;
+const analysis = require('../../lib/index');
+
+test('spec', t => {
+    t.type(analysis, 'function');
+    t.end();
+});
diff --git a/test/unit/utility.js b/test/unit/utility.js
new file mode 100644
index 0000000..ee220bd
--- /dev/null
+++ b/test/unit/utility.js
@@ -0,0 +1,19 @@
+const test = require('tap').test;
+const utility = require('../../lib/utility');
+
+test('spec', t => {
+    t.type(utility, 'function');
+    t.type(utility.frequency, 'function');
+    t.end();
+});
+
+test('frequency', t => {
+    const input = ['foo', 'foo', 'foo', 'bar', 'bar', 'baz'];
+    const result = utility.frequency(input);
+    t.deepEqual(result, {
+        foo: 3,
+        bar: 2,
+        baz: 1
+    });
+    t.end();
+});