WIP deferred engine load!

part of #610
part of the merge of #608

most unit tests working, only a few left - due to me hanging a property off the engine that @geoffp was not doing.
still need to see how it behaves during actual builds

Author: bmuenzenmeyer

.eslintrc

@@ -83,6 +83,10 @@
     "space-infix-ops": 1,
     "valid-typeof": 2,
     "vars-on-top": 0,
-    "wrap-iife": [2, "inside"]
+    "wrap-iife": [2, "inside"],
+    "prefer-const": ["error", {
+      "destructuring": "any",
+      "ignoreReadBeforeAssign": false
+      }]
   }
 }

core/lib/annotation_exporter.js

@@ -1,23 +1,23 @@
-"use strict";
+'use strict';
+const path = require('path');
+const glob = require('glob');
+const fs = require('fs-extra');
+const JSON5 = require('json5');
+const _ = require('lodash');
+const mp = require('./markdown_parser');
 
-var path = require('path'),
-  glob = require('glob'),
-  fs = require('fs-extra'),
-  JSON5 = require('json5'),
-  _ = require('lodash'),
-  mp = require('./markdown_parser');
+const annotations_exporter = function (pl) {
 
-var annotations_exporter = function (pl) {
-
-  var paths = pl.config.paths;
+  const paths = pl.config.paths;
+  let oldAnnotations;
 
   /*
   Returns the array of comments that used to be wrapped in raw JS.
    */
   function parseAnnotationsJS() {
     //attempt to read the file
     try {
-      var oldAnnotations = fs.readFileSync(path.resolve(paths.source.annotations, 'annotations.js'), 'utf8');
+      oldAnnotations = fs.readFileSync(path.resolve(paths.source.annotations, 'annotations.js'), 'utf8');
     } catch (ex) {
       if (pl.config.debug) {
         console.log('annotations.js file missing from ' + paths.source.annotations + '. This may be expected.');
@@ -40,8 +40,8 @@ var annotations_exporter = function (pl) {
   }
 
   function buildAnnotationMD(annotationsYAML, markdown_parser) {
-    var annotation = {};
-    var markdownObj = markdown_parser.parse(annotationsYAML);
+    const annotation = {};
+    const markdownObj = markdown_parser.parse(annotationsYAML);
 
     annotation.el = markdownObj.el || markdownObj.selector;
     annotation.title = markdownObj.title;
@@ -50,16 +50,16 @@ var annotations_exporter = function (pl) {
   }
 
   function parseMDFile(annotations, parser) {
-    var annotations = annotations;
-    var markdown_parser = parser;
+    //let annotations = annotations;
+    const markdown_parser = parser;
 
     return function (filePath) {
-      var annotationsMD = fs.readFileSync(path.resolve(filePath), 'utf8');
+      const annotationsMD = fs.readFileSync(path.resolve(filePath), 'utf8');
 
     //take the annotation snippets and split them on our custom delimiter
-      var annotationsYAML = annotationsMD.split('~*~');
-      for (var i = 0; i < annotationsYAML.length; i++) {
-        var annotation = buildAnnotationMD(annotationsYAML[i], markdown_parser);
+      const annotationsYAML = annotationsMD.split('~*~');
+      for (let i = 0; i < annotationsYAML.length; i++) {
+        const annotation = buildAnnotationMD(annotationsYAML[i], markdown_parser);
         annotations.push(annotation);
       }
       return false;
@@ -70,17 +70,17 @@ var annotations_exporter = function (pl) {
    Converts the *.md file yaml list into an array of annotations
    */
   function parseAnnotationsMD() {
-    var markdown_parser = new mp();
-    var annotations = [];
-    var mdFiles = glob.sync(paths.source.annotations + '/*.md');
+    const markdown_parser = new mp();
+    const annotations = [];
+    const mdFiles = glob.sync(paths.source.annotations + '/*.md');
 
     mdFiles.forEach(parseMDFile(annotations, markdown_parser));
     return annotations;
   }
 
   function gatherAnnotations() {
-    var annotationsJS = parseAnnotationsJS();
-    var annotationsMD = parseAnnotationsMD();
+    const annotationsJS = parseAnnotationsJS();
+    const annotationsMD = parseAnnotationsMD();
     return _.unionBy(annotationsJS, annotationsMD, 'el');
   }
 

core/lib/changes_hunter.js

@@ -1,12 +1,12 @@
-"use strict";
-const fs = require("fs-extra"),
-  CompileState = require('./object_factory').CompileState;
+'use strict';
+const fs = require("fs-extra");
+const CompileState = require('./object_factory').CompileState;
 
 /**
  * For detecting changed patterns.
  * @constructor
  */
-let ChangesHunter = function () {
+const ChangesHunter = function () {
 };
 
 ChangesHunter.prototype = {
@@ -24,11 +24,11 @@ ChangesHunter.prototype = {
   checkBuildState: function (pattern, patternlab) {
 
     //write the compiled template to the public patterns directory
-    let renderedTemplatePath =
+    const renderedTemplatePath =
       patternlab.config.paths.public.patterns + pattern.getPatternLink(patternlab, 'rendered');
 
     //write the compiled template to the public patterns directory
-    let markupOnlyPath =
+    const markupOnlyPath =
       patternlab.config.paths.public.patterns + pattern.getPatternLink(patternlab, 'markupOnly');
 
     if (!pattern.compileState) {
@@ -45,7 +45,7 @@ ChangesHunter.prototype = {
         // Prevent error message if file does not exist
         fs.accessSync(renderedFile, fs.F_OK)
       );
-      let outputLastModified = fs.statSync(renderedTemplatePath).mtime.getTime();
+      const outputLastModified = fs.statSync(renderedTemplatePath).mtime.getTime();
 
       if (pattern.lastModified && outputLastModified > pattern.lastModified) {
         pattern.compileState = CompileState.CLEAN;
@@ -55,7 +55,7 @@ ChangesHunter.prototype = {
       pattern.compileState = CompileState.NEEDS_REBUILD;
     }
 
-    let node = patternlab.graph.node(pattern);
+    const node = patternlab.graph.node(pattern);
 
     // Make the pattern known to the PatternGraph and remember its compileState
     if (!node) {
@@ -78,7 +78,7 @@ ChangesHunter.prototype = {
   checkLastModified: function (currentPattern, file) {
     if (file) {
       try {
-        let stat = fs.statSync(file);
+        const stat = fs.statSync(file);
 
         // Needs recompile whenever one of the patterns files (template, json, pseudopatterns) changed
         currentPattern.lastModified =

core/lib/lineage_hunter.js

@@ -1,30 +1,30 @@
-"use strict";
+'use strict';
+const extend = require("util")._extend;
 
-var extend = require("util")._extend;
+const lineage_hunter = function () {
 
-var lineage_hunter = function () {
+  function findlineage(pattern, patternlab) {
 
-  var pa = require('./pattern_assembler');
+    const pa = require('./pattern_assembler');
+    const pattern_assembler = new pa();
 
-  function findlineage(pattern, patternlab) {
     // As we are adding edges from pattern to ancestor patterns, ensure it is known to the graph
     patternlab.graph.add(pattern);
 
-    var pattern_assembler = new pa();
 
     //find the {{> template-name }} within patterns
-    var matches = pattern.findPartials();
+    const matches = pattern.findPartials();
     if (matches !== null) {
       matches.forEach(function (match) {
         //get the ancestorPattern
-        var ancestorPattern = pattern_assembler.getPartial(pattern.findPartial(match), patternlab);
+        const ancestorPattern = pattern_assembler.getPartial(pattern.findPartial(match), patternlab);
 
         if (ancestorPattern && pattern.lineageIndex.indexOf(ancestorPattern.patternPartial) === -1) {
           //add it since it didnt exist
           pattern.lineageIndex.push(ancestorPattern.patternPartial);
 
           //create the more complex patternLineage object too
-          var l = {
+          const l = {
             "lineagePattern": ancestorPattern.patternPartial,
             "lineagePath": "../../patterns/" + ancestorPattern.patternLink
           };
@@ -44,7 +44,7 @@ var lineage_hunter = function () {
             ancestorPattern.lineageRIndex.push(pattern.patternPartial);
 
             //create the more complex patternLineage object in reverse
-            var lr = {
+            const lr = {
               "lineagePattern": pattern.patternPartial,
               "lineagePath": "../../patterns/" + pattern.patternLink
             };
@@ -69,15 +69,15 @@ var lineage_hunter = function () {
    * @param graph {PatternGraph}
    */
   function setPatternState(direction, pattern, targetPattern, graph) {
-    var index = null;
+    let index = null;
     if (direction === 'fromPast') {
       index = graph.lineage(pattern);
     } else {
       index = graph.lineageR(pattern);
     }
 
     // if the request came from the past, apply target pattern state to current pattern lineage
-    for (var i = 0; i < index.length; i++) {
+    for (let i = 0; i < index.length; i++) {
       if (index[i].patternPartial === targetPattern.patternPartial) {
         index[i].lineageState = targetPattern.patternState;
       }
@@ -87,36 +87,36 @@ var lineage_hunter = function () {
 
   function cascadePatternStates(patternlab) {
 
-    for (var i = 0; i < patternlab.patterns.length; i++) {
-      var pattern = patternlab.patterns[i];
+    for (let i = 0; i < patternlab.patterns.length; i++) {
+      const pattern = patternlab.patterns[i];
 
       //for each pattern with a defined state
       if (pattern.patternState) {
-        var lineage = patternlab.graph.lineage(pattern);
+        const lineage = patternlab.graph.lineage(pattern);
 
         if (lineage && lineage.length > 0) {
 
           //find all lineage - patterns being consumed by this one
-          for (var h = 0; h < lineage.length; h++) {
+          for (let h = 0; h < lineage.length; h++) {
             // Not needed, the graph already knows the concrete pattern
-            // var lineagePattern = pattern_assembler.getPartial(lineageIndex[h], patternlab);
+            // let lineagePattern = pattern_assembler.getPartial(lineageIndex[h], patternlab);
             setPatternState('fromFuture', lineage[h], pattern, patternlab.graph);
           }
         }
-        var lineageR = patternlab.graph.lineageR(pattern);
+        const lineageR = patternlab.graph.lineageR(pattern);
         if (lineageR && lineageR.length > 0) {
 
           //find all reverse lineage - that is, patterns consuming this one
-          for (var j = 0; j < lineageR.length; j++) {
+          for (let j = 0; j < lineageR.length; j++) {
 
-            var lineageRPattern = lineageR[j];
+            const lineageRPattern = lineageR[j];
 
             //only set patternState if pattern.patternState "is less than" the lineageRPattern.patternstate
             //or if lineageRPattern.patternstate (the consuming pattern) does not have a state
             //this makes patternlab apply the lowest common ancestor denominator
-            let patternStateCascade = patternlab.config.patternStateCascade;
-            let patternStateIndex = patternStateCascade.indexOf(pattern.patternState);
-            let patternReverseStateIndex = patternStateCascade.indexOf(lineageRPattern.patternState);
+            const patternStateCascade = patternlab.config.patternStateCascade;
+            const patternStateIndex = patternStateCascade.indexOf(pattern.patternState);
+            const patternReverseStateIndex = patternStateCascade.indexOf(lineageRPattern.patternState);
             if (lineageRPattern.patternState === '' || (patternStateIndex < patternReverseStateIndex)) {
 
               if (patternlab.config.debug) {