Improve extractAssets to minimize memory and CPU consumption

packages/mdctl-core/streams/section.js

@@ -37,7 +37,7 @@ const _ = require('lodash'),
         },
       },
       NON_WRITABLE_KEYS = ['facet'],
-      SectionsCreated = [],
+      sectionsWithResources = [],
       { privatesAccessor } = require('@medable/mdctl-core-utils/privates'),
       crypto = require('crypto')
 
@@ -51,16 +51,25 @@ class ExportSection {
       scriptFiles: [],
       extraFiles: [],
       templateFiles: [],
+      resourcePaths: [],
       id: uuid.v4()
     })
     if (new.target === ExportSection) {
       Object.seal(this)
     }
     if (this.isWritable) {
-      SectionsCreated.push(this)
+      const nodes = jp.nodes(content, '$..resourceId')
+      if (nodes.length > 0) {
+        privatesAccessor(this).resourcePaths.push(...nodes)
+        sectionsWithResources.push(this)
+      }
     }
   }
 
+  static clearSectionsWithResources() {
+    sectionsWithResources.length = 0
+  }
+
   get id() {
     return privatesAccessor(this).id
   }
@@ -85,6 +94,10 @@ class ExportSection {
     return privatesAccessor(this).templateFiles
   }
 
+  get resourcePaths() {
+    return privatesAccessor(this).resourcePaths
+  }
+
   get name() {
     const { content, key } = privatesAccessor(this),
           {
@@ -183,10 +196,9 @@ class ExportSection {
   extractAssets() {
     const facet = privatesAccessor(this).content
     let itemSource = null
-    for (let i = 0; i < SectionsCreated.length; i += 1) {
-      const sc = SectionsCreated[i],
-            nodes = jp.nodes(sc.content, '$..resourceId'),
-            item = _.find(nodes, n => n.value === facet.resourceId)
+    for (let i = 0; i < sectionsWithResources.length; i += 1) {
+      const sc = sectionsWithResources[i],
+            item = _.find(sc.resourcePaths, n => n.value === facet.resourceId)
       if (item) {
         // replace last path
         const ETagPathItem = _.clone(item.path)