Update to latest rdf-canon N-Quads canonical form.

**BREAKING**: Use latest rdf-canon N-Quads canonical form. This can
change the canonical output! There is an expanded set of control
characters that are escaped as an `ECHAR` or `UCHAR` instead of using a
native representation.

CHANGELOG.md

@@ -6,6 +6,10 @@
 - Test with karma.
 
 ### Changed
+- **BREAKING**: Use latest [rdf-canon][] N-Quads canonical form. This can
+  change the canonical output! There is an expanded set of control characters
+  that are escaped as an `ECHAR` or `UCHAR` instead of using a native
+  representation.
 - **BREAKING**: Use `globalThis` to access `crypto` in browsers. Use a polyfill
   if your environment doesn't support `globalThis`.
 - Update tooling.

lib/NQuads.js

@@ -381,7 +381,7 @@ function _compareTriples(t1, t2) {
   );
 }
 
-const _stringLiteralEscapeRegex = /["\\\n\r]/g;
+const _stringLiteralEscapeRegex = /[\u0000-\u001F\u007F"\\]/g;
 /**
  * Escape string to N-Quads literal
  */
@@ -391,16 +391,25 @@ function _stringLiteralEscape(s) {
   }
   return s.replace(_stringLiteralEscapeRegex, function(match) {
     switch(match) {
-      case '"': return '\\"';
-      case '\\': return '\\\\';
+      case '\b': return '\\b';
+      case '\t': return '\\t';
       case '\n': return '\\n';
+      case '\f': return '\\f';
       case '\r': return '\\r';
+      case '"': return '\\"';
+      case '\\': return '\\\\';
+      case '\u007F': return '\\u007F';
     }
+    return '\\u' + match
+      .codePointAt(0)
+      .toString(16)
+      .toUpperCase()
+      .padStart(4, '0');
   });
 }
 
 const _stringLiteralUnescapeRegex =
-  /(?:\\([tbnrf"'\\]))|(?:\\u([0-9A-Fa-f]{4}))|(?:\\U([0-9A-Fa-f]{8}))/g;
+  /(?:\\([btnfr"'\\]))|(?:\\u([0-9A-Fa-f]{4}))|(?:\\U([0-9A-Fa-f]{8}))/g;
 /**
  * Unescape N-Quads literal to string
  */
@@ -411,11 +420,11 @@ function _stringLiteralUnescape(s) {
   return s.replace(_stringLiteralUnescapeRegex, function(match, code, u, U) {
     if(code) {
       switch(code) {
-        case 't': return '\t';
         case 'b': return '\b';
+        case 't': return '\t';
         case 'n': return '\n';
-        case 'r': return '\r';
         case 'f': return '\f';
+        case 'r': return '\r';
         case '"': return '"';
         case '\'': return '\'';
         case '\\': return '\\';