Add compactToRelative option.

Author: gkellogg

lib/jsonld.js

@@ -96,6 +96,8 @@ const wrapper = function(jsonld) {
  *          [base] the base IRI to use.
  *          [compactArrays] true to compact arrays to single values when
  *            appropriate, false not to (default: true).
+ *          [compactToRelative] true to compact IRIs to be relative to document base,
+ *            false to keep absolute (default: true)
  *          [graph] true to always output a top-level graph (default: false).
  *          [expandContext] a context to expand with.
  *          [skipExpansion] true to assume the input is expanded and skip
@@ -134,6 +136,7 @@ jsonld.compact = util.callbackify(async function(input, ctx, options) {
   options = _setDefaults(options, {
     base: _isString(input) ? input : '',
     compactArrays: true,
+    compactToRelative: true,
     graph: false,
     skipExpansion: false,
     link: false,
@@ -144,6 +147,9 @@ jsonld.compact = util.callbackify(async function(input, ctx, options) {
     // API, it should only be called from framing
     options.skipExpansion = true;
   }
+  if(!options.compactToRelative) {
+    delete options.base;
+  }
 
   // expand input
   let expanded;