Compact graphs with @container: @graph and @id or @index.

- adds a BNode issuer to compact to generate identifiers, if necessary.

Author: gkellogg

lib/compact.js

@@ -45,7 +45,8 @@ module.exports = api;
  * @param activeProperty the compacted property associated with the element
  *          to compact, null for none.
  * @param element the element to compact.
- * @param options the compaction options.
+ * @param options the compaction options:
+ *          [issuer] a jsonld.IdentifierIssuer to use to label blank nodes.
  * @param compactionMap the compaction map to use.
  *
  * @return the compacted value.
@@ -126,6 +127,9 @@ api.compact = ({
 
     const rval = {};
 
+    // produce a map of all subjects and name each bnode
+    const issuer = options.issuer || new util.IdentifierIssuer('_:b');
+
     if(options.link && '@id' in element) {
       // store linked element
       if(!(element['@id'] in options.link)) {
@@ -262,20 +266,20 @@ api.compact = ({
           activeCtx, itemActiveProperty, '@container') || [];
 
         // get simple @graph or @list value if appropriate
-        const isSimpleGraph = _isSimpleGraph(expandedItem);
+        const isGraph = _isGraph(expandedItem);
         const isList = _isList(expandedItem);
         let inner;
         if(isList) {
           inner = expandedItem['@list'];
-        } else if(isSimpleGraph) {
+        } else if(isGraph) {
           inner = expandedItem['@graph'];
         }
 
         // recursively compact expanded item
         let compactedItem = api.compact({
           activeCtx,
           activeProperty: itemActiveProperty,
-          element: (isList || isSimpleGraph) ? inner : expandedItem,
+          element: (isList || isGraph) ? inner : expandedItem,
           options,
           compactionMap
         });
@@ -309,22 +313,63 @@ api.compact = ({
           }
         }
 
-        // handle simple @graph
-        if(isSimpleGraph && !container.includes('@graph')) {
-          // wrap using @graph alias
-          compactedItem = {
-            [api.compactIri({activeCtx, iri: '@graph'})]: compactedItem
-          };
-
-          // include @index from expanded @graph, if any
-          if('@index' in expandedItem) {
-            compactedItem[api.compactIri({activeCtx, iri: '@index'})] =
-              expandedItem['@index'];
-          }
-        }
+        // Graph object compaction cases
+        if(isGraph) {
+          if(container.includes('@graph') && container.includes('@id')) {
+            // container includes @graph and @id
+            // get or create the map object
+            let mapObject;
+            if(itemActiveProperty in rval) {
+              mapObject = rval[itemActiveProperty];
+            } else {
+              rval[itemActiveProperty] = mapObject = {};
+            }
+            // add compactedItem to map, using value of `@id` or a new blank node identifier
+            _addValue(
+              mapObject, (expandedItem['@id'] || issuer.getId(null)), compactedItem,
+              {propertyIsArray: (!options.compactArrays || container.includes('@set'))});
+          } else if(container.includes('@graph') && container.includes('@index') && _isSimpleGraph(expandedItem)) {
+            // container includes @graph and @index and item is a simple graph
+            // get or create the map object
+            let mapObject;
+            if(itemActiveProperty in rval) {
+              mapObject = rval[itemActiveProperty];
+            } else {
+              rval[itemActiveProperty] = mapObject = {};
+            }
+            // add compactedItem to map, using value of `@index` or `@none`
+            _addValue(
+              mapObject, (expandedItem['@index'] || '@none'), compactedItem,
+              {propertyIsArray: (!options.compactArrays || container.includes('@set'))});
+          } else if(container.includes('@graph') && _isSimpleGraph(expandedItem)) {
+            // container includes @graph but not @id or @index and value is a simple graph object
+            // add compact value
+            _addValue(
+              rval, itemActiveProperty, compactedItem,
+              {propertyIsArray: (!options.compactArrays || container.includes('@set'))});
+          } else {
+            // wrap using @graph alias
+            compactedItem = {
+              [api.compactIri({activeCtx, iri: '@graph'})]: compactedItem
+            };
 
+            // include @id from expanded graph, if any
+            if('@id' in expandedItem) {
+              compactedItem[api.compactIri({activeCtx, iri: '@id'})] =
+                expandedItem['@id'];
+            }
+
+            // include @index from expanded graph, if any
+            if('@index' in expandedItem) {
+              compactedItem[api.compactIri({activeCtx, iri: '@index'})] =
+                expandedItem['@index'];
+            }
+            _addValue(
+              rval, itemActiveProperty, compactedItem,
+              {propertyIsArray: (!options.compactArrays || container.includes('@set'))});
+          }
+        } else if(container.includes('@language') || container.includes('@index')) {
         // handle language and index maps
-        if(container.includes('@language') || container.includes('@index')) {
           // get or create the map object
           let mapObject;
           if(itemActiveProperty in rval) {
@@ -412,9 +457,12 @@ api.compactIri = ({
       containers.push('@index');
     }
 
-    // prefer `['@graph', '@set']` and then `@graph` if value is a simple graph
-    // TODO: support `@graphId`?
+    // prefer most specific container including @graph, prefering @set variations
     if(_isGraph(value)) {
+      containers.push('@graph@index@set');
+      containers.push('@graph@index');
+      containers.push('@graph@id@set');
+      containers.push('@graph@id');
       containers.push('@graph@set');
       containers.push('@graph');
     }

lib/jsonld.js

@@ -136,7 +136,8 @@ jsonld.compact = util.callbackify(async function(input, ctx, options) {
     compactArrays: true,
     graph: false,
     skipExpansion: false,
-    link: false
+    link: false,
+    issuer: new IdentifierIssuer('_:b')
   });
   if(options.link) {
     // force skip expansion when linking, "link" is not part of the public

tests/test-common.js

@@ -29,7 +29,7 @@ const manifest = options.manifest || {
 const TEST_TYPES = {
   'jld:CompactTest': {
     skip: {
-      regex: [/#t0073/, /#t[acmnps]/, /#t008[1-8]/]
+      regex: [/#t0073/, /#t[acmnps]/]
     },
     fn: 'compact',
     params: [