Code files

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/.gitignore

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+node_modules
+*.log

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/example.js

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+var hsl = require('./')
+var hue = 133
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/index.js

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+// In our case, there's only one dependency
+
+var toRgb = require('hsl-to-rgb-for-reals')
+var debug = require('debug')('hsl-to-hex')
+
+// 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) {
+  debug('ensuring ' + val + ' is no more than ' + n)
+  return (val > n) ? n : val
+}
+
+function min (val, n) {
+  debug('ensuring ' + val + ' is no less than ' + n)
+  return (val < n) ? n : val
+}
+
+function cycle (val) {
+  debug('resolving ' + val + ' within the 0-359 range')
+
+  // 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) {
+  debug('calculating hex for hue: ' + hue + ' saturation: ' + saturation + ' luminosity: ' + 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

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/package.json

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+{
+  "name": "@davidmarkclements/hsl-to-hex",
+  "version": "1.0.1",
+  "main": "index.js",
+  "scripts": {
+    "check": "npm ls && npm test",
+    "test": "npm run lint && tap --cov test",
+    "lint": "standard",
+    "prepublish": "npm run check && ./publish-dep.sh"
+  },
+  "author": "David Mark Clements",
+  "license": "ISC",
+  "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": {
+    "debug": "^2.2.0",
+    "hsl-to-rgb-for-reals": "^1.1.0"
+  },
+  "devDependencies": {
+    "standard": "^6.0.8",
+    "tap": "^5.7.0"
+  },
+  "directories": {
+    "test": "test"
+  }
+}

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/publish-dep.sh

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+#! /bin/sh
+
+# 400 - Missing hash and/or peer_id
+# 403 - Not allowed
+# 413 - Too big
+# 200 - Ok!
+
+
+if echo $npm_config_argv | grep -q "install"; then
+  echo "Running at install step, skipping"
+else
+  if ipfs &>/dev/null; then
+    echo "## Publishing dependency"
+
+    mv node_modules .node_modules 2>/dev/null
+
+    HASH=$(ipfs add . -r | tail -n 1 | cut -d ' ' -f 2)
+
+    mv .node_modules node_modules 2>/dev/null
+
+    echo "Published as $HASH"
+
+    PEER=$(ipfs id --format '<id>')
+
+    if [ -f ~/.stay/nodes.json ]; then
+      cat ~/.stay/nodes.json | jq -rc '.[]' | while read host; do
+        address="$host/api/pin/add/$HASH/$PEER"
+        status=$(curl -X POST --silent $address)
+        case "$status" in
+          "400")  echo "$host - Application Error: Missing the hash and/or peer_id"
+            ;;
+          "403")  echo  "$host - You do not have access to pinning at this node"
+            ;;
+          "413")  echo  "$host - The module was too big to pin!"
+            ;;
+          "200") echo  "$host - Pinned!"
+            ;;
+          *) echo "Weird status code $status for $host"
+            ;;
+        esac
+      done
+    else
+      echo "You don't have any saved nodes in ~/.stay/nodes.json, skip pinning"
+    fi
+  else
+    echo "## Could not publish dependency to IPFS, doing the good'ol 'fetch from npm registry' way"
+    echo "Either 'ipfs' doesn't exists in PATH or you haven't run 'ipfs daemon' before running the command"
+    exit 0
+  fi
+fi

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/readme.md

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+# 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
+var saturation = 40
+var luminosity = 60
+var hex = hsl(hue, saturation, luminosity)
+console.log(hex) // #70c282
+```
+
+## License
+
+ISC

Chapter02/publishing-a-module/decentralized-publishing/hsl-to-hex/test/index.js

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+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()
+})