Make loading single file work without scanning whole collection

src/valueObjects/Collection.js

@@ -0,0 +1,109 @@
+import { FOLDER, FILES } from '../constants/collectionTypes';
+
+function formatToExtension(format) {
+  return {
+    markdown: 'md',
+    yaml: 'yml',
+    json: 'json',
+    html: 'html',
+  }[format];
+}
+
+class FolderCollection {
+  constructor(collection) {
+    this.collection = collection;
+  }
+
+  entryFields() {
+    return this.collection.get('fields');
+  }
+
+  entryPath(slug) {
+    return `${ this.collection.get('folder') }/${ slug }.${ this.entryExtension() }`;
+  }
+
+  entrySlug(path) {
+    return path.split('/').pop().replace(/\.[^\.]+$/, '');
+  }
+
+  listMethod() {
+    return 'entriesByFolder';
+  }
+
+  entryExtension() {
+    return this.collection.get('extension') || formatToExtension(this.collection.get('format') || 'markdown');
+  }
+
+  allowNewEntries() {
+    return this.collection.get('create');
+  }
+}
+
+class FilesCollection {
+  constructor(collection) {
+    this.collection = collection;
+  }
+
+  entryFields(slug) {
+    const file = this.fileForEntry(slug);
+    return file && file.get('fields');
+  }
+
+  entryPath(slug) {
+    const file = this.fileForEntry(slug);
+    return file && file.get('file');
+  }
+
+  entrySlug(path) {
+    const file = this.collection.get('files').filter(f => f.get('file') === path).get(0);
+    return file && file.get('name');
+  }
+
+  fileForEntry(slug) {
+    const files = this.collection.get('files');
+    return files.filter(f => f.get('name') === slug).get(0);
+  }
+
+  listMethod() {
+    return 'entriesByFiles';
+  }
+
+  allowNewEntries() {
+    return false;
+  }
+}
+
+export default class Collection {
+  constructor(collection) {
+    switch (collection.get('type')) {
+      case FOLDER:
+        this.collection = new FolderCollection(collection);
+        break;
+      case FILES:
+        this.collection = new FilesCollection(collection);
+        break;
+      default:
+        throw ('Unknown collection type: %o', collection.get('type'));
+    }
+  }
+
+  entryFields(slug) {
+    return this.collection.entryFields(slug);
+  }
+
+  entryPath(slug) {
+    return this.collection.entryPath(slug);
+  }
+
+  entrySlug(path) {
+    return this.collection.entrySlug(path);
+  }
+
+  listMethod() {
+    return this.collection.listMethod();
+  }
+
+  allowNewEntries() {
+    return this.collection.allowNewEntries();
+  }
+}