Dynamically generate routes in prerender

Author: Salma Alam-Naylor

.gitignore

@@ -37,3 +37,6 @@ testem.log
 # System Files
 .DS_Store
 Thumbs.db
+
+# Routes
+_routes.txt

_routes.txt

@@ -31,7 +31,9 @@
     "dev:ssr": "ng run fretonator-web:serve-ssr",
     "serve:ssr": "node dist/fretonator-web/server/main.js",
     "build:ssr": "ng build --prod && ng run fretonator-web:server:production",
-    "prerender": "ng run fretonator-web:prerender --routesFile _routes.txt"
+    "prerender": "run-s prerender:*",
+    "prerender:routes": "nx workspace-schematic generate-routes",
+    "prerender:build": "ng run fretonator-web:prerender --routesFile _routes.txt"
   },
   "private": true,
   "dependencies": {
@@ -70,6 +72,7 @@
     "eslint": "6.8.0",
     "jest": "25.2.3",
     "jest-preset-angular": "8.1.2",
+    "npm-run-all": "^4.1.5",
     "prettier": "2.0.4",
     "ts-jest": "^26.1.0",
     "ts-node": "~7.0.0",

package.json

@@ -0,0 +1,19 @@
+import { Rule, Tree } from '@angular-devkit/schematics';
+import generateModeRoutes from './mode-routes';
+import writeRoutes from './write-routes';
+
+export default function(schema: any): Rule {
+  return (tree: Tree) => {
+    const staticPages = [
+      '/',
+      '/about',
+      '/404'
+    ];
+
+    const modeRoutes = generateModeRoutes();
+
+    // writeRoutes(tree, [...staticPages, ...modeRoutes]);
+
+    return writeRoutes(tree, [...staticPages, ...modeRoutes]);
+  };
+}

tools/schematics/generate-routes/index.ts

@@ -0,0 +1,75 @@
+function cartesianProduct(arr) {
+  return arr.reduce(function(a, b) {
+    return a.map(function(x) {
+      return b.map(function(y) {
+        return x.concat([y]);
+      });
+    }).reduce(function(a, b) {
+      return a.concat(b);
+    }, []);
+  }, [[]]);
+}
+
+enum NoteExtenderString {
+  sharp = 'sharp',
+  natural = 'natural',
+  flat = 'flat'
+}
+
+enum Mode {
+  ionian = 'ionian',
+  dorian = 'dorian',
+  phrygian = 'phrygian',
+  lydian = 'lydian',
+  mixolydian = 'mixolydian',
+  aolian = 'aolian',
+  locrian = 'locrian',
+  harmonicMinor = 'harmonicMinor',
+  phrygianDominant = 'phrygianDominant',
+  majorPentatonic = 'majorPentatonic',
+  minorPentatonic = 'minorPentatonic'
+}
+
+const Octave = ['a', 'b', 'c', 'd', 'e', 'f', 'g'];
+
+enum NoteSymbol {
+  aFlat = 'a_',
+  a = 'a',
+  aSharp = 'a#',
+  bFlat = 'b_',
+  b = 'b',
+  c = 'c',
+  cSharp = 'c#',
+  dFlat = 'd_',
+  d = 'd',
+  dSharp = 'd#',
+  eFlat = 'e_',
+  e = 'e',
+  f = 'f',
+  fSharp = 'f#',
+  gFlat = 'g_',
+  g = 'g',
+  gSharp = 'g#',
+}
+
+enum NoteExtenderSymbol {
+  sharp = '#',
+  natural = '',
+  flat = '_'
+}
+
+export default (): string[] => {
+  const octave = Octave;
+  const noteExtender = Object.values(NoteExtenderString);
+  const mode = Object.values(Mode);
+  const product = cartesianProduct([octave, noteExtender, mode]);
+
+  return product
+    .filter(([key, extender, mode]) => {
+      const extenderSymbol = NoteExtenderSymbol[extender];
+      const validCombination = Object.values(NoteSymbol).find(value => value === `${key}${extenderSymbol}`);
+      return Boolean(validCombination);
+    })
+    .map(combination => ['', ...combination].join('/'));
+}
+

tools/schematics/generate-routes/mode-routes/index.ts

@@ -0,0 +1,16 @@
+{
+  "$schema": "http://json-schema.org/schema",
+  "id": "generate-routes",
+  "type": "object",
+  "properties": {
+    "name": {
+      "type": "string",
+      "description": "Library name",
+      "$default": {
+        "$source": "argv",
+        "index": 0
+      }
+    }
+  },
+  "required": []
+}

tools/schematics/generate-routes/schema.json

@@ -0,0 +1,20 @@
+import { Tree } from '@angular-devkit/schematics';
+
+export default (tree: Tree, routes: string[]) => {
+  const flatRoutes = routes.join('\n');
+  const outFile = '_routes.txt';
+
+  if(!tree.exists(outFile)) {
+    tree.create(outFile, flatRoutes);
+    return null;
+  }
+
+  const { content } = tree.get(outFile);
+
+  if(content.toString() !== flatRoutes) {
+    tree.overwrite(outFile, flatRoutes);
+    return null;
+  }
+
+  return null;
+}