WIP: Framing

CHANGELOG.md

@@ -16,12 +16,21 @@
 - Keywords may not be used as prefixes.
 - Handle term definition on `@type` with empty map.
 - Handling of `@` values for `@reverse`.
+- Changes in object embedding.
+- Better support for graph framing.
+- Better frame validation.
+- Wildcard matching on `@id` and other `requireAll` semantics.
 
 ### Changed
 - Keep term definitions mapping to null so they may be protected.
 - **NOTE**: `LINK_HEADER_REL` in `lib/constants.js` has been deprecated and
   renamed to `LINK_HEADER_CONTEXT`. It remains for now but will be removed in a
   future release.
+- Changed framing defaults
+  - `embed` to "@once" and warn on "@first" or "@last".
+  - `pruneBlankNodeIdentifiers` based on processingMode.
+  - `omitGraph` based on processingMode.
+- Replaced `removePreserve` with `cleanupPreserve` and `cleanupNulls`.
 
 ### Added
 - Support for `"@import"`.
@@ -30,6 +39,9 @@
 - Support for expansion and compaction of values container `"@direction"`.
 - Support for RDF transformation of `@direction` when `rdfDirection` is
   'i18n-datatype'.
+- Top level `@graph` omitted if `omitGraph` is `true`.
+- Check for invalid values of `@embed`.
+- Support default values for `@type` when framing.
 
 ## 2.0.2 - 2020-01-17
 

lib/compact.js

@@ -1067,95 +1067,6 @@ api.compactValue = ({activeCtx, activeProperty, value, options}) => {
   };
 };
 
-/**
- * Removes the @preserve keywords as the last step of the compaction
- * algorithm when it is running on framed output.
- *
- * @param ctx the active context used to compact the input.
- * @param input the framed, compacted output.
- * @param options the compaction options used.
- *
- * @return the resulting output.
- */
-api.removePreserve = (ctx, input, options) => {
-  // recurse through arrays
-  if(_isArray(input)) {
-    const output = [];
-    for(let i = 0; i < input.length; ++i) {
-      const result = api.removePreserve(ctx, input[i], options);
-      // drop nulls from arrays
-      if(result !== null) {
-        output.push(result);
-      }
-    }
-    input = output;
-  } else if(_isObject(input)) {
-    // remove @preserve
-    if('@preserve' in input) {
-      if(input['@preserve'] === '@null') {
-        return null;
-      }
-      return input['@preserve'];
-    }
-
-    // skip @values
-    if(_isValue(input)) {
-      return input;
-    }
-
-    // recurse through @lists
-    if(_isList(input)) {
-      input['@list'] = api.removePreserve(ctx, input['@list'], options);
-      return input;
-    }
-
-    // handle in-memory linked nodes
-    const idAlias = api.compactIri({
-      activeCtx: ctx,
-      iri: '@id',
-      relativeTo: {vocab: true}
-    });
-    if(input.hasOwnProperty(idAlias)) {
-      const id = input[idAlias];
-      if(options.link.hasOwnProperty(id)) {
-        const idx = options.link[id].indexOf(input);
-        if(idx !== -1) {
-          // already visited
-          return options.link[id][idx];
-        }
-        // prevent circular visitation
-        options.link[id].push(input);
-      } else {
-        // prevent circular visitation
-        options.link[id] = [input];
-      }
-    }
-
-    // recurse through properties
-    const graphAlias = api.compactIri({
-      activeCtx: ctx,
-      iri: '@graph',
-      relativeTo: {vocab: true}
-    });
-    for(const prop in input) {
-      // potentially remove the id, if it is an unreference bnode
-      if(prop === idAlias && options.bnodesToClear.includes(input[prop])) {
-        delete input[idAlias];
-        continue;
-      }
-
-      let result = api.removePreserve(ctx, input[prop], options);
-      const container = _getContextValue(ctx, prop, '@container') || [];
-      if(options.compactArrays && _isArray(result) && result.length === 1 &&
-        container.length === 0 && prop !== graphAlias) {
-        result = result[0];
-      }
-      input[prop] = result;
-    }
-  }
-  return input;
-};
-
 /**
  * Picks the preferred compaction term from the given inverse context entry.
  *

lib/context.js

@@ -1284,12 +1284,12 @@ api.getContextValue = (ctx, key, type) => {
   }
 
   // get default language
-  if(type === '@language' && ctx.hasOwnProperty(type)) {
+  if(type === '@language' && type in ctx) {
     return ctx[type];
   }
 
   // get default direction
-  if(type === '@direction' && ctx.hasOwnProperty(type)) {
+  if(type === '@direction' && type in ctx) {
     return ctx[type];
   }
 

lib/expand.js

@@ -466,8 +466,7 @@ async function _expandObject({
       }
       if(expandedProperty in expandedParent &&
          expandedProperty !== '@included' &&
-         expandedProperty !== '@type')
-      {
+         expandedProperty !== '@type') {
         throw new JsonLdError(
           'Invalid JSON-LD syntax; colliding keywords detected.',
           'jsonld.SyntaxError',
@@ -515,7 +514,17 @@ async function _expandObject({
     }
 
     if(expandedProperty === '@type') {
-      _validateTypeValue(value);
+      // if framing, can be a default object, but need to expand
+      // key to determine that
+      if(_isObject(value)) {
+        value = Object.fromEntries(Object.entries(value).map(([k, v]) => [
+          _expandIri(typeScopedContext, k, {vocab: true}),
+          _asArray(v).map(vv =>
+            _expandIri(typeScopedContext, vv, {base: true, vocab: true})
+          )
+        ]));
+      }
+      _validateTypeValue(value, options.isFrame);
       _addValue(
         expandedParent, '@type',
         _asArray(value).map(v =>