feat(main): enable custom derived category

README.md

@@ -69,6 +69,7 @@ formatter.preFormat(micropubDocument)
 * **noMarkdown** – if set to `true` then no conversion to Markdown will happen for the content.
 * **contentSlug** – if set to `true`, then the slug creation will use the `properties.content` data as a fallback to `properties.name` prior to basing the slug on the timestamp.
 * **defaults** – a `micropubDocument` with defaults that will be added as part of the `preFormat()`. Useful to eg. ensure that all documents have a language explicitly set.
+* **deriveCategory** – a method that's provided the properties of the post and which returns a dervice category – or `false` to disable default category deriving
 * **deriveLanguages** – an array defining what languages, using [ISO 639-3](https://en.wikipedia.org/wiki/ISO_639-3), to autodetect – or `true` to try and autodetect everything
 * **permalinkStyle** – a Jekyll [permalink style](https://jekyllrb.com/docs/permalinks/). Defaults to Jekyll's default: `date`
 

index.js

@@ -56,6 +56,7 @@ const Formatter = function (options) {
   this.defaults = options.defaults;
   this.deriveLanguages = options.deriveLanguages || false;
   this.permalinkStyle = options.permalinkStyle;
+  this.deriveCategory = options.deriveCategory === undefined ? true : options.deriveCategory;
 };
 
 Formatter.prototype._resolveFrontMatterData = function (data) {
@@ -257,7 +258,14 @@ Formatter.prototype.preFormat = function (data) {
     }
   }
 
-  if (
+  if (typeof this.deriveCategory === 'function') {
+    data.derived.category = this.deriveCategory(data.properties);
+    if (!data.derived.category) {
+      delete data.derived.category;
+    }
+  } else if (!this.deriveCategory) {
+    // Do nothing
+  } else if (
     !_.isEmpty(data.properties.bookmark) ||
     !_.isEmpty(data.properties['repost-of']) ||
     !_.isEmpty(data.properties['bookmark-of'])

test/formatter.spec.js

@@ -402,6 +402,17 @@ describe('Formatter', function () {
       return formatter.preFormat(baseMicroformatData).should.eventually.not.have.deep.property('derived.category');
     });
 
+    it('should not derive interaction category when opted out of', function () {
+      formatter = new Formatter({ deriveCategory: false });
+      baseMicroformatData.properties['in-reply-to'] = ['http://example.com/replied/to/page'];
+      return formatter.preFormat(baseMicroformatData).should.eventually.not.have.deep.property('derived.category');
+    });
+
+    it('should use result of deriveCategory() method when provided', function () {
+      formatter = new Formatter({ deriveCategory: () => 'foo' });
+      return formatter.preFormat(baseMicroformatData).should.eventually.have.deep.property('derived.category', 'foo');
+    });
+
     it('should extract person tags from regular tags', function () {
       baseMicroformatData.properties.category = ['http://example.com/', 'foo', 'http://example.net/'];
       return formatter.preFormat(baseMicroformatData).then(function (result) {