Add more typographer replacement rules

lib/rules_core/replacements.js

@@ -1,4 +1,4 @@
-// Simple typographyc replacements
+// Simple typographic replacements
 //
 // '' → ‘’
 // "" → “”. Set '«»' for Russian, '„“' for German, empty to disable
@@ -6,6 +6,10 @@
 // (tm) (TM) → ™
 // (r) (R) → ®
 // +- → ±
+// <3 → ♥
+// <-> → ↔
+// <- → ←
+// -> → →
 // (p) (P) -> §
 // ... → … (also ?.... → ?.., !.... → !..)
 // ???????? → ???, !!!!! → !!!, `,,` → `,`
@@ -17,7 +21,7 @@
 // - fractionals 1/2, 1/4, 3/4 -> ½, ¼, ¾
 // - miltiplication 2 x 4 -> 2 × 4
 
-var RARE_RE = /\+-|\.\.|\?\?\?\?|!!!!|,,|--/;
+var RARE_RE = /\+-|<3|->|<-|\.\.|\?\?\?\?|!!!!|,,|--/;
 
 var SCOPED_ABBR_RE = /\((c|tm|r|p)\)/ig;
 var SCOPED_ABBR = {
@@ -56,6 +60,10 @@ module.exports = function replace(state) {
 
         if (RARE_RE.test(text)) {
           text = text.replace(/\+-/g, '±')
+                     .replace(/<3/g,  '♥')
+                     .replace(/<->/g, '↔')
+                     .replace(/<-/g,  '←')
+                     .replace(/->/g,  '→')
                       // .., ..., ....... -> …
                       // but ?..... & !..... -> ?.. & !..
                       .replace(/\.{2,}/g, '…').replace(/([?!])…/g, '$1..')

support/demo_template/sample.md

@@ -31,7 +31,7 @@ ___
 
 Enable typographer option to see result.
 
-(c) (C) (r) (R) (tm) (TM) (p) (P) +-
+(c) (C) (r) (R) (tm) (TM) (p) (P) +- <3 <-> <- ->
 
 test.. test... test..... test?..... test!....
 

test/fixtures/markdown-it/typographer.txt

@@ -45,6 +45,38 @@ plus-minus
 .
 
 
+heart
+.
+<3
+.
+<p>♥</p>
+.
+
+
+leftarrow
+.
+<-
+.
+<p>←</p>
+.
+
+
+rightarrow
+.
+->
+.
+<p>→</p>
+.
+
+
+leftrightarrow
+.
+<->
+.
+<p>↔</p>
+.
+
+
 ellipsis
 .
 test.. test... test..... test?..... test!....