and get an account. Keep the npm username handy, we're going to need it.
+
### How to do it
+If we've just signed up for an npm account (as explained in the previous [Getting Ready](#getting-ready-4) section) we'll want to authorise our `npm` client with [npmjs.org](http://npmjs.org).
+
+On the command line, we simply need to run:
+
+```sh
+npm login
+```
+Then supply the username, password, and email address we signed up with.
+
+Every module should have a Readme explaining how it works.
+
+Let's create a Readme.md file with the following markdown:
+
+
+# hsl-to-hex
+
+Convert HSL colors to RGB colors in hex format.
+
+## Install
+
+```sh
+npm install --save @davidmarkclements/hsl-to-hex
+```
+
+## API
+
+```
+require('hsl-to-hex') => Function
+hsl(hue, saturation, luminosity)` => String
+```
+
+## Example
+
+```js
+var hsl = require('hsl-to-hex')
+var hue = 133 hsl(133, 40, 60)
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282
+```
+
+## License
+
+ISC
+
+
+In the install section of the readme, we should replace `@davidmarkclements/hsl-to-hex` with out own username.
+
+> #### Markdown 
+> Markdown is a lightweight documentation syntax, see
+>
+
+As a courtesy, we'll also take the example we wrote in the Readme and
+put it in an `example.js` file.
+
+Let's create a file called `example.js` with the following contents:
+
+```js
+var hsl = require('hsl-to-hex')
+var hue = 133 hsl(133, 40, 60)
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282
+```
+
+Now we'll make some final touches the `package.json` file.
+
+First we'll reinitialize the module:
+
+```sh
+npm init
+```
+
+Following this command, we can simply press Enter in response to all questions. The output of `npm init` should show that a `description` field has been added, with its content taken from the `readme.md` file.
+
+```json
+ "description": "Convert HSL colors to RGB colors in hex format.",
+```
+
+Now let's open the `package.json` file and change the `name` field,
+by prefixing it with an at (`@`) symbol, followed by our npm username,
+followed by a forward slash (`/`). For instance:
+
+```json
+ "name": "@davidmarkclements/hsl-to-hex",
+```
+
+Of course, instead of using `@davidmarkclements` we'll use whatever username with supplied to `npm login`.
+
+Finally we're ready to publish:
+
+```sh
+npm install --access public
+```
+
### How it works
### There's more
#### Listing Installed Modules
-#### Module Security Audit
-
#### Bundling Dependencies
+#### Everything Everywhere
+
### See also
+* TODO LATER
+
## Using a private repository
### Getting ready
@@ -867,8 +1181,16 @@ configuring npm author etc.
### There's more
+#### Module Security Audit
+
+#### Scope Registries
+
+
+
### See also
+* TODO LATER
+
diff --git a/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/example.js b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/example.js
new file mode 100644
index 0000000..7eab9ed
--- /dev/null
+++ b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/example.js
@@ -0,0 +1,6 @@
+var hsl = require('hsl-to-hex')
+var hue = 133 hsl(133, 40, 60)
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282
\ No newline at end of file
diff --git a/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/index.js b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/index.js
new file mode 100644
index 0000000..6a623e7
--- /dev/null
+++ b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/index.js
@@ -0,0 +1,59 @@
+// In our case, there's only one dependency
+
+var toRgb = require('hsl-to-rgb-for-reals')
+
+// Typically all dependencies should be declared at the top of the file.
+
+// Now let's define an API for our module, we're taking hue, saturation and luminosity values and outputting a CSS compatible hex string.
+// Hue is in degrees, between 0 and 359. Since degrees a cyclical in nature, we'll support numbers greater than 359 or less than 0 by "spinning" them around until they fall within the 0 to 359 range.
+// Saturation and luminosity are both percentages, we'll represent these percentages with whole numbers between 0 and 100. For these numbers we'll need to enforce a maximum and a minimum, anything below 0 will become 0, anything above 100 will become 100.
+// Let's write some utility functions to handle this logic:
+
+function max (val, n) {
+ return (val > n) ? n : val
+}
+
+function min (val, n) {
+ return (val < n) ? n : val
+}
+
+function cycle (val) {
+ // for safety:
+ val = max(val, 1e7)
+ val = min(val, -1e7)
+ // cycle value:
+ while (val < 0) { val += 360 }
+ while (val > 359) { val -= 360 }
+ return val
+}
+
+// Now for the main piece, the `hsl` function:
+
+function hsl (hue, saturation, luminosity) {
+ // resolve degrees to 0 - 359 range
+ hue = cycle(hue)
+
+ // enforce constraints
+ saturation = min(max(saturation, 100), 0)
+ luminosity = min(max(luminosity, 100), 0)
+
+ // convert to 0 to 1 range used by hsl-to-rgb-for-reals
+ saturation /= 100
+ luminosity /= 100
+
+ // let hsl-to-rgb-for-reals do the hard work
+ var rgb = toRgb(hue, saturation, luminosity)
+
+ // convert each value in the returned RGB array
+ // to a 2 character hex value, join the array into
+ // a string, prefixed with a hash
+ return '#' + rgb
+ .map(function (n) {
+ return (256 + n).toString(16).substr(-2)
+ })
+ .join('')
+}
+
+// In order to make our code into a bona fide module we have to export it:
+
+module.exports = hsl
diff --git a/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/package.json b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/package.json
new file mode 100644
index 0000000..1df7817
--- /dev/null
+++ b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/package.json
@@ -0,0 +1,30 @@
+{
+ "name": "hsl-to-hex",
+ "version": "1.0.0",
+ "main": "index.js",
+ "scripts": {
+ "test": "npm run lint && tap --cov test",
+ "lint": "standard"
+ },
+ "author": "David Mark Clements",
+ "license": "MIT",
+ "repository": {
+ "type": "git",
+ "url": "git+ssh://git@github.com/davidmarkclements/hsl-to-hex.git"
+ },
+ "bugs": {
+ "url": "https://github.com/davidmarkclements/hsl-to-hex/issues"
+ },
+ "homepage": "https://github.com/davidmarkclements/hsl-to-hex#readme",
+ "description": "Convert HSL colors to RGB colors in hex format.",
+ "dependencies": {
+ "hsl-to-rgb-for-reals": "^1.1.0"
+ },
+ "devDependencies": {
+ "standard": "^6.0.8",
+ "tap": "^5.7.0"
+ },
+ "directories": {
+ "test": "test"
+ }
+}
diff --git a/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/readme.md b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/readme.md
new file mode 100644
index 0000000..3d509dd
--- /dev/null
+++ b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/readme.md
@@ -0,0 +1,25 @@
+# hsl-to-hex
+
+Convert HSL colors to RGB colors in hex format.
+
+## API
+
+```
+require('hsl-to-hex') => Function
+hsl(hue, saturation, luminosity)` => String
+```
+
+## Example
+
+```js
+var hsl = require('hsl-to-hex')
+var hue = 133 hsl(133, 40, 60)
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282
+```
+
+## License
+
+ISC
\ No newline at end of file
diff --git a/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/test/index.js b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/test/index.js
new file mode 100644
index 0000000..b355f31
--- /dev/null
+++ b/1-Writing-Modules/source/publishing-a-module/hsl-to-hex/test/index.js
@@ -0,0 +1,74 @@
+var hsl = require('../')
+var test = require('tap').test
+
+test('pure white', function (assert) {
+ var expected = '#ffffff'
+ var actual = hsl(0, 100, 100)
+ var it = 'max saturation and luminosity should return pure white'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('medium gray', function (assert) {
+ var expected = '#808080'
+ var actual = hsl(0, 0, 50)
+ var it = '0% saturation, 50% luminosity should be medium gray'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('hue - red', function (assert) {
+ var expected = '#ff0000'
+ var actual = hsl(0, 100, 50)
+ var it = '0deg should be red'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('hue - blue', function (assert) {
+ var expected = '#0000ff'
+ var actual = hsl(240, 100, 50)
+ var it = '240deg should be blue'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('hue - cyan', function (assert) {
+ var expected = '#00ffff'
+ var actual = hsl(180, 100, 50)
+ var it = '180deg should be cyan'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('degree overflow', function (assert) {
+ var expected = hsl(1, 100, 50)
+ var actual = hsl(361, 100, 50)
+ var it = '361deg should be the same as 1deg'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('degree underflow', function (assert) {
+ var expected = hsl(-1, 100, 50)
+ var actual = hsl(359, 100, 50)
+ var it = '-1deg should be the same as 359deg'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('max constraint', function (assert) {
+ var expected = hsl(0, 101, 50)
+ var actual = hsl(0, 100, 50)
+ var it = '101% should be the same as 100%'
+ assert.is(actual, expected, it)
+ assert.end()
+})
+
+test('min constraint', function (assert) {
+ var expected = hsl(0, -1, 50)
+ var actual = hsl(0, 0, 50)
+ var it = '-1% should be the same as 0%'
+ assert.is(actual, expected, it)
+ assert.end()
+})
diff --git a/1-Writing-Modules/source/writing-module-code/adding-tests/hsl-to-hex/test/index.js b/1-Writing-Modules/source/writing-module-code/adding-tests/hsl-to-hex/test/index.js
index a7c0ab7..b355f31 100644
--- a/1-Writing-Modules/source/writing-module-code/adding-tests/hsl-to-hex/test/index.js
+++ b/1-Writing-Modules/source/writing-module-code/adding-tests/hsl-to-hex/test/index.js
@@ -65,7 +65,7 @@ test('max constraint', function (assert) {
assert.end()
})
-test('max constraint', function (assert) {
+test('min constraint', function (assert) {
var expected = hsl(0, -1, 50)
var actual = hsl(0, 0, 50)
var it = '-1% should be the same as 0%'
diff --git a/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/index.js b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/index.js
new file mode 100644
index 0000000..6a623e7
--- /dev/null
+++ b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/index.js
@@ -0,0 +1,59 @@
+// In our case, there's only one dependency
+
+var toRgb = require('hsl-to-rgb-for-reals')
+
+// Typically all dependencies should be declared at the top of the file.
+
+// Now let's define an API for our module, we're taking hue, saturation and luminosity values and outputting a CSS compatible hex string.
+// Hue is in degrees, between 0 and 359. Since degrees a cyclical in nature, we'll support numbers greater than 359 or less than 0 by "spinning" them around until they fall within the 0 to 359 range.
+// Saturation and luminosity are both percentages, we'll represent these percentages with whole numbers between 0 and 100. For these numbers we'll need to enforce a maximum and a minimum, anything below 0 will become 0, anything above 100 will become 100.
+// Let's write some utility functions to handle this logic:
+
+function max (val, n) {
+ return (val > n) ? n : val
+}
+
+function min (val, n) {
+ return (val < n) ? n : val
+}
+
+function cycle (val) {
+ // for safety:
+ val = max(val, 1e7)
+ val = min(val, -1e7)
+ // cycle value:
+ while (val < 0) { val += 360 }
+ while (val > 359) { val -= 360 }
+ return val
+}
+
+// Now for the main piece, the `hsl` function:
+
+function hsl (hue, saturation, luminosity) {
+ // resolve degrees to 0 - 359 range
+ hue = cycle(hue)
+
+ // enforce constraints
+ saturation = min(max(saturation, 100), 0)
+ luminosity = min(max(luminosity, 100), 0)
+
+ // convert to 0 to 1 range used by hsl-to-rgb-for-reals
+ saturation /= 100
+ luminosity /= 100
+
+ // let hsl-to-rgb-for-reals do the hard work
+ var rgb = toRgb(hue, saturation, luminosity)
+
+ // convert each value in the returned RGB array
+ // to a 2 character hex value, join the array into
+ // a string, prefixed with a hash
+ return '#' + rgb
+ .map(function (n) {
+ return (256 + n).toString(16).substr(-2)
+ })
+ .join('')
+}
+
+// In order to make our code into a bona fide module we have to export it:
+
+module.exports = hsl
diff --git a/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/package.json b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/package.json
new file mode 100644
index 0000000..307f7a5
--- /dev/null
+++ b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/package.json
@@ -0,0 +1,27 @@
+{
+ "name": "hsl-to-hex",
+ "version": "1.0.0",
+ "main": "index.js",
+ "scripts": {
+ "test": "npm run lint && tap --node-arg='--harmony-destructuring' --cov test",
+ "lint": "standard"
+ },
+ "author": "David Mark Clements",
+ "license": "MIT",
+ "repository": {
+ "type": "git",
+ "url": "git+ssh://git@github.com/davidmarkclements/hsl-to-hex.git"
+ },
+ "bugs": {
+ "url": "https://github.com/davidmarkclements/hsl-to-hex/issues"
+ },
+ "homepage": "https://github.com/davidmarkclements/hsl-to-hex#readme",
+ "description": "",
+ "dependencies": {
+ "hsl-to-rgb-for-reals": "^1.1.0"
+ },
+ "devDependencies": {
+ "standard": "^6.0.8",
+ "tap": "^5.7.0"
+ }
+}
diff --git a/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/test/index.js b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/test/index.js
new file mode 100644
index 0000000..8b0f99a
--- /dev/null
+++ b/1-Writing-Modules/source/writing-module-code/modernizing-syntax/hsl-to-hex/test/index.js
@@ -0,0 +1,90 @@
+const hsl = require('../')
+const {test} = require('tap')
+
+test('pure white', ({is, end}) => {
+ const expected = '#ffffff'
+ const actual = hsl(0, 100, 100)
+ const it = `
+ max saturation and luminosity should return pure white
+ `
+ is(actual, expected, it)
+ end()
+})
+
+test('medium gray', ({is, end}) => {
+ const expected = '#808080'
+ const actual = hsl(0, 0, 50)
+ const it = `
+ 0% saturation, 50% luminosity should be medium gray
+ `
+ is(actual, expected, it)
+ end()
+})
+
+test('hue', ({is, end}) => {
+ {
+ const expected = '#ff0000'
+ const actual = hsl(0, 100, 50)
+ const it = `
+ 0deg should be red
+ `
+ is(actual, expected, it)
+ }
+ {
+ const expected = '#0000ff'
+ const actual = hsl(240, 100, 50)
+ const it = `
+ 240deg should be blue
+ `
+ is(actual, expected, it)
+ }
+ {
+ const expected = '#00ffff'
+ const actual = hsl(180, 100, 50)
+ const it = `
+ 180deg should be cyan
+ `
+ is(actual, expected, it)
+ }
+ end()
+})
+
+test('degree overflow/underflow', ({is, end}) => {
+ {
+ const expected = hsl(1, 100, 50)
+ const actual = hsl(361, 100, 50)
+ const it = `
+ 361deg should be the same as 1deg
+ `
+ is(actual, expected, it)
+ }
+ {
+ const expected = hsl(-1, 100, 50)
+ const actual = hsl(359, 100, 50)
+ const it = `
+ -1deg should be the same as 359deg
+ `
+ is(actual, expected, it)
+ }
+ end()
+})
+
+test('max constraint', ({is, end}) => {
+ {
+ const expected = hsl(0, 101, 50)
+ const actual = hsl(0, 100, 50)
+ const it = `
+ 101% should be the same as 100%
+ `
+ is(actual, expected, it)
+ }
+ {
+ const expected = hsl(0, -1, 50)
+ const actual = hsl(0, 0, 50)
+ const it = `
+ -1% should be the same as 0%
+ `
+ is(actual, expected, it)
+ }
+ end()
+})