Fix usage of JS Object property names in data.

- Fixed usage of JavaScript Object property names in data.
  - **NOTE**: A class of bugs was causing term names such as `toString`,
    `valueOf`, and others to be dropped or produce bogus output. The fix could
    cause output triples to differ from previous versions if those special
    names were used.
  - Specifically, the problem was using `x in obj` instead of
    `obj.hasOwnProperty(x)` or a `Map`.
  - Fixed usage in contexts for expand and compact.
  - Attempted fixes in other parts of the code with similar `x in obj` usage.
    Finding actual realistic failing test cases proved difficult.
  - Help would be appreciated making test cases or finding other locations with
    a similar issue.
- A few cleanups.

Author: davidlehn

CHANGELOG.md

@@ -1,7 +1,21 @@
 # jsonld ChangeLog
 
+## 1.6.0 - 2019-03-xx
+
 ### Fixed
 - Testing: Use explicit id and description skipping regexes.
+- Usage of JavaScript Object property names in data.
+  - **NOTE**: A class of bugs was causing term names such as `toString`,
+    `valueOf`, and others to be dropped or produce bogus output. The fix could
+    cause output triples to differ from previous versions if those special
+    names were used.
+  - Specifically, the problem was using `x in obj` instead of
+    `obj.hasOwnProperty(x)` or a `Map`.
+  - Fixed usage in contexts for expand and compact.
+  - Attempted fixes in other parts of the code with similar `x in obj` usage.
+    Finding actual realistic failing test cases proved difficult.
+  - Help would be appreciated making test cases or finding other locations with
+    a similar issue.
 
 ### Changed
 - Testing: Improve skip logging.

lib/compact.js

@@ -113,7 +113,8 @@ api.compact = ({
 
   // recursively compact object
   if(_isObject(element)) {
-    if(options.link && '@id' in element && element['@id'] in options.link) {
+    if(options.link && '@id' in element &&
+      options.link.hasOwnProperty(element['@id'])) {
       // check for a linked element to reuse
       const linked = options.link[element['@id']];
       for(let i = 0; i < linked.length; ++i) {
@@ -129,7 +130,7 @@ api.compact = ({
         api.compactValue({activeCtx, activeProperty, value: element, options});
       if(options.link && _isSubjectReference(element)) {
         // store linked element
-        if(!(element['@id'] in options.link)) {
+        if(!(options.link.hasOwnProperty(element['@id']))) {
           options.link[element['@id']] = [];
         }
         options.link[element['@id']].push({expanded: element, compacted: rval});
@@ -144,7 +145,7 @@ api.compact = ({
 
     if(options.link && '@id' in element) {
       // store linked element
-      if(!(element['@id'] in options.link)) {
+      if(!options.link.hasOwnProperty(element['@id'])) {
         options.link[element['@id']] = [];
       }
       options.link[element['@id']].push({expanded: element, compacted: rval});
@@ -208,8 +209,8 @@ api.compact = ({
 
         // handle double-reversed properties
         for(const compactedProperty in compactedValue) {
-          if(activeCtx.mappings[compactedProperty] &&
-            activeCtx.mappings[compactedProperty].reverse) {
+          if(activeCtx.mappings.has(compactedProperty) &&
+            activeCtx.mappings.get(compactedProperty).reverse) {
             const value = compactedValue[compactedProperty];
             const container = _getContextValue(
               activeCtx, compactedProperty, '@container') || [];
@@ -297,8 +298,8 @@ api.compact = ({
           relativeTo: {vocab: true},
           reverse: insideReverse
         });
-        const nestProperty = (itemActiveProperty in activeCtx.mappings) ?
-          activeCtx.mappings[itemActiveProperty]['@nest'] : null;
+        const nestProperty = activeCtx.mappings.has(itemActiveProperty) ?
+          activeCtx.mappings.get(itemActiveProperty)['@nest'] : null;
         let nestResult = rval;
         if(nestProperty) {
           _checkNestProperty(activeCtx, nestProperty, options);
@@ -326,8 +327,8 @@ api.compact = ({
 
         // if itemActiveProperty is a @nest property, add values to nestResult,
         // otherwise rval
-        const nestProperty = (itemActiveProperty in activeCtx.mappings) ?
-          activeCtx.mappings[itemActiveProperty]['@nest'] : null;
+        const nestProperty = activeCtx.mappings.has(itemActiveProperty) ?
+          activeCtx.mappings.get(itemActiveProperty)['@nest'] : null;
         let nestResult = rval;
         if(nestProperty) {
           _checkNestProperty(activeCtx, nestProperty, options);
@@ -384,7 +385,7 @@ api.compact = ({
                 relativeTo: {vocab: true}
               })] = expandedItem['@index'];
             }
-          } else if(itemActiveProperty in nestResult) {
+          } else if(nestResult.hasOwnProperty(itemActiveProperty)) {
             // can't use @list container for more than 1 list
             throw new JsonLdError(
               'JSON-LD compact error; property has a "@list" @container ' +
@@ -401,7 +402,7 @@ api.compact = ({
             container.includes('@index') && _isSimpleGraph(expandedItem))) {
             // get or create the map object
             let mapObject;
-            if(itemActiveProperty in nestResult) {
+            if(nestResult.hasOwnProperty(itemActiveProperty)) {
               mapObject = nestResult[itemActiveProperty];
             } else {
               nestResult[itemActiveProperty] = mapObject = {};
@@ -472,7 +473,7 @@ api.compact = ({
           // handle language and index maps
           // get or create the map object
           let mapObject;
-          if(itemActiveProperty in nestResult) {
+          if(nestResult.hasOwnProperty(itemActiveProperty)) {
             mapObject = nestResult[itemActiveProperty];
           } else {
             nestResult[itemActiveProperty] = mapObject = {};
@@ -736,7 +737,7 @@ api.compactIri = ({
       if(iri.indexOf(vocab) === 0 && iri !== vocab) {
         // use suffix as relative iri if it is not a term in the active context
         const suffix = iri.substr(vocab.length);
-        if(!(suffix in activeCtx.mappings)) {
+        if(!activeCtx.mappings.has(suffix)) {
           return suffix;
         }
       }
@@ -767,9 +768,9 @@ api.compactIri = ({
       // 2. value is null, which means we're not compacting an @value, AND
       //   the mapping matches the IRI
       const curie = term + ':' + iri.substr(entry.iri.length);
-      const isUsableCurie = (activeCtx.mappings[term]._prefix &&
-        (!(curie in activeCtx.mappings) ||
-        (value === null && activeCtx.mappings[curie]['@id'] === iri)));
+      const isUsableCurie = (activeCtx.mappings.get(term)._prefix &&
+        (!activeCtx.mappings.has(curie) ||
+        (value === null && activeCtx.mappings.get(curie)['@id'] === iri)));
 
       // select curie if it is shorter or the same length but lexicographically
       // less than the current choice
@@ -834,8 +835,8 @@ api.compactValue = ({activeCtx, activeProperty, value, options}) => {
       (keyCount === 2 && '@index' in value && !preserveIndex));
     const hasDefaultLanguage = ('@language' in activeCtx);
     const isValueString = _isString(value['@value']);
-    const hasNullMapping = (activeCtx.mappings[activeProperty] &&
-      activeCtx.mappings[activeProperty]['@language'] === null);
+    const hasNullMapping = (activeCtx.mappings.has(activeProperty) &&
+      activeCtx.mappings.get(activeProperty)['@language'] === null);
     if(isValueOnlyKey &&
       (!hasDefaultLanguage || !isValueString || hasNullMapping)) {
       return value['@value'];
@@ -948,9 +949,9 @@ api.removePreserve = (ctx, input, options) => {
       iri: '@id',
       relativeTo: {vocab: true}
     });
-    if(idAlias in input) {
+    if(input.hasOwnProperty(idAlias)) {
       const id = input[idAlias];
-      if(id in options.link) {
+      if(options.link.hasOwnProperty(id)) {
         const idx = options.link[id].indexOf(input);
         if(idx !== -1) {
           // already visited
@@ -1020,9 +1021,9 @@ function _selectTerm(
     // try to compact value to a term
     const term = api.compactIri(
       {activeCtx, iri: value['@id'], relativeTo: {vocab: true}});
-    if(term in activeCtx.mappings &&
-      activeCtx.mappings[term] &&
-      activeCtx.mappings[term]['@id'] === value['@id']) {
+    if(activeCtx.mappings.has(term) &&
+      activeCtx.mappings.get(term) &&
+      activeCtx.mappings.get(term)['@id'] === value['@id']) {
       // prefer @vocab
       prefs.push.apply(prefs, ['@vocab', '@id']);
     } else {