diff --git a/lab-david/.eslintignore b/lab-david/.eslintignore
new file mode 100644
index 0000000..82ff623
--- /dev/null
+++ b/lab-david/.eslintignore
@@ -0,0 +1,5 @@
+**/node_modules/*
+**/vendor/*
+**/*.min.js
+**/coverage/*
+**/build/*
\ No newline at end of file
diff --git a/lab-david/.eslintrc.json b/lab-david/.eslintrc.json
new file mode 100644
index 0000000..3fe56a5
--- /dev/null
+++ b/lab-david/.eslintrc.json
@@ -0,0 +1,27 @@
+{
+    "env": {
+      "browser": true,
+      "node": true,
+      "commonjs": true,
+      "jest": true,
+      "es6": true
+    },
+    "globals": {
+      "err": true,
+      "req": true,
+      "res": true,
+      "next": true
+    },
+    "extends": "eslint:recommended",
+    "parserOptions": {
+      "sourceType": "module"
+    },
+    "rules": {
+      "no-console": "off",
+      "indent": [ "error", 2 ],
+      "quotes": ["error", "single", { "allowTemplateLiterals": true }],
+      "comma-dangle": ["error", "always-multiline"],
+      "semi": [ "error", "always" ],
+      "linebreak-style": ["error", "unix"]
+    }
+  }
\ No newline at end of file
diff --git a/lab-david/.gitignore b/lab-david/.gitignore
new file mode 100644
index 0000000..e24c600
--- /dev/null
+++ b/lab-david/.gitignore
@@ -0,0 +1,145 @@
+# 401 JS
+db
+**.env
+temp
+build
+
+# Created by https://www.gitignore.io/api/vim,osx,node,linux,windows
+### Linux ###
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+### Node ###
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Typescript v1 declaration files
+typings/
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variables file
+.env
+
+
+### OSX ###
+*.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+### Vim ###
+# swap
+[._]*.s[a-v][a-z]
+[._]*.sw[a-p]
+[._]s[a-v][a-z]
+[._]sw[a-p]
+# session
+Session.vim
+# temporary
+.netrwhist
+# auto-generated tag files
+tags
+
+### Windows ###
+# Windows thumbnail cache files
+Thumbs.db
+ehthumbs.db
+ehthumbs_vista.db
+
+# Folder config file
+Desktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+# End of https://www.gitignore.io/api/vim,osx,node,linux,windows
\ No newline at end of file
diff --git a/lab-david/README.md b/lab-david/README.md
new file mode 100644
index 0000000..c9b7a3a
--- /dev/null
+++ b/lab-david/README.md
@@ -0,0 +1,14 @@
+### 01-Node-Ecosystem
+
+Greet Module
+* Single function module
+* Airty of one
+* Expects a string argument, otherwise it will throw an error
+* Returns a string concatenating "Hello" with the entered string
+
+Arithmetic Module
+* Two methods within module (add, sub)
+* Both methods have an airty of two
+* Both methods expect two number arguments, otherwise they will throw errors
+* add return the sum of the two arguments
+* sub returns the difference between the minuend and subtrahend
diff --git a/lab-david/index.js b/lab-david/index.js
new file mode 100644
index 0000000..673845c
--- /dev/null
+++ b/lab-david/index.js
@@ -0,0 +1,4 @@
+'use strict';
+
+const greet = require('./lib/greet.js');
+const arithmetic = require('./lib/arithmetic.js');
diff --git a/lab-david/lib/arithmetic.js b/lab-david/lib/arithmetic.js
new file mode 100644
index 0000000..fe6c362
--- /dev/null
+++ b/lab-david/lib/arithmetic.js
@@ -0,0 +1,15 @@
+'use strict';
+
+module.exports = exports = {};
+
+exports.add = function(a,b){
+    if(typeof(a) !== 'number' || typeof(b) !== 'number') throw new Error('Those aren\'t numbers');
+    console.log(a + b);
+    return a + b;
+}
+
+exports.sub = function(a,b){
+    if(typeof(a) !== 'number' || typeof(b) !== 'number') throw new Error('Those aren\'t numbers');
+    console.log(a - b);
+    return a - b;
+}
\ No newline at end of file
diff --git a/lab-david/lib/greet.js b/lab-david/lib/greet.js
new file mode 100644
index 0000000..72f9f26
--- /dev/null
+++ b/lab-david/lib/greet.js
@@ -0,0 +1,7 @@
+'use strict';
+
+module.exports = function(name){
+    if(typeof(name) !== 'string') throw new Error ('You didn\'t enter a string');
+    console.log(`Hello ${name}`);
+    return `Hello ${name}`;
+}
\ No newline at end of file
diff --git a/lab-david/test/arithmetic-test.js b/lab-david/test/arithmetic-test.js
new file mode 100644
index 0000000..5ed5911
--- /dev/null
+++ b/lab-david/test/arithmetic-test.js
@@ -0,0 +1,29 @@
+'use strict';
+
+const arithmetic = require('../lib/arithmetic.js');
+const assert = require('assert');
+
+describe('Arithmetic Module', function(){
+    describe('#add', function() {
+        it('Should add 8 to 10 to return 18', function(){
+            var result = arithmetic.add(8, 10);
+            assert.ok(result === 18, 'Not equal to 18');
+        })
+        it('Should return null', function(){
+            assert.throws(function(){
+                arithmetic.add('not a number', 'also not a number')
+            }, 'Error not thrown');
+        });
+    });
+    describe('#sub', function(){
+        it('Should subtract 4 from 10 to return 6', function(){
+            var result = arithmetic.sub(10,4);
+            assert.ok(result === 6, 'Not equal to 6');
+        });
+        it('Should return null', function(){
+            assert.throws(function(){
+                arithmetic.add('not a number', 'also not a number')
+            }, 'Error not thrown');
+        });
+    });
+});
\ No newline at end of file
diff --git a/lab-david/test/greet-test.js b/lab-david/test/greet-test.js
new file mode 100644
index 0000000..cdeaeca
--- /dev/null
+++ b/lab-david/test/greet-test.js
@@ -0,0 +1,16 @@
+'use strict';
+
+const greet = require('../lib/greet.js')
+const assert = require('assert');
+
+describe('Greet Module', function(){
+    it('Should say Hello David', function(){
+        var result = greet('David');
+        assert.ok(result === 'Hello David', 'Doesn\'t say Hello David');
+    });
+    it('Should return null', function(){
+        assert.throws(function(){
+            greet();
+        }, 'Not an error');
+    })
+})
\ No newline at end of file