Add skipExpansion flag to toRdf and canonize.

Author: dlongley

CHANGELOG.md

@@ -1,5 +1,8 @@
 # jsonld ChangeLog
 
+### Added
+- Add `skipExpansion` flag to `toRdf` and `canonize`.
+
 ## 1.0.4 - 2018-08-17
 
 ### Fixed

lib/jsonld.js

@@ -516,6 +516,8 @@ jsonld.link = util.callbackify(async function(input, ctx, options) {
  *            `URGNA2012` (default: `URGNA2012`).
  *          [base] the base IRI to use.
  *          [expandContext] a context to expand with.
+ *          [skipExpansion] true to assume the input is expanded and skip
+ *            expansion, false not to, defaults to false.
  *          [inputFormat] the format if input is not JSON-LD:
  *            'application/n-quads' for N-Quads.
  *          [format] the format if output is a string:
@@ -534,7 +536,8 @@ jsonld.normalize = jsonld.canonize = util.callbackify(async function(
   // set default options
   options = _setDefaults(options, {
     base: _isString(input) ? input : '',
-    algorithm: 'URDNA2015'
+    algorithm: 'URDNA2015',
+    skipExpansion: false
   });
   if('inputFormat' in options) {
     if(options.inputFormat !== 'application/n-quads' &&
@@ -639,6 +642,8 @@ jsonld.fromRDF = util.callbackify(async function(dataset, options) {
  * @param [options] the options to use:
  *          [base] the base IRI to use.
  *          [expandContext] a context to expand with.
+ *          [skipExpansion] true to assume the input is expanded and skip
+ *            expansion, false not to, defaults to false.
  *          [format] the format to use to output a string:
  *            'application/n-quads' for N-Quads.
  *          [produceGeneralizedRdf] true to output generalized RDF, false
@@ -655,13 +660,18 @@ jsonld.toRDF = util.callbackify(async function(input, options) {
 
   // set default options
   options = _setDefaults(options, {
-    base: _isString(input) ? input : ''
+    base: _isString(input) ? input : '',
+    skipExpansion: false
   });
 
   // TODO: support toRDF custom map?
-
-  // expand input
-  const expanded = await jsonld.expand(input, options);
+  let expanded;
+  if(options.skipExpansion) {
+    expanded = input;
+  } else {
+    // expand input
+    expanded = await jsonld.expand(input, options);
+  }
 
   // output RDF dataset
   const dataset = _toRDF(expanded, options);