implement "special symbols" (switch certain strings for utf-8 symbols), fixes #3140

app/assets/javascripts/app/helpers/text_formatter.js

@@ -53,6 +53,30 @@
       return text;
     });
 
+    // make nice little utf-8 symbols
+    converter.hooks.chain("preConversion", function(text) {
+      var input_strings = [
+        "<->", "->", "<-",
+        "(c)", "(r)", "(tm)",
+        "<3"
+      ];
+      var output_symbols = [
+        "↔", "→", "←",
+        "©", "®", "™",
+        "♥"
+      ];
+      // quote function from: http://stackoverflow.com/a/494122
+      var quote = function(str) {
+        return str.replace(/([.?*+^$[\]\\(){}|-])/g, "\\$1");
+      };
+
+      _.each(input_strings, function(str, idx) {
+        var r = new RegExp(quote(str), "gi");
+        text = text.replace(r, output_symbols[idx]);
+      });
+      return text;
+    });
+
     converter.hooks.chain("postConversion", function (text) {
       return text.replace(/(\"(?:(?:http|https):\/\/)?[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(?:\/\S*)?\")(\>)/g, '$1 target="_blank">')
     });

spec/javascripts/app/helpers/text_formatter_spec.js

@@ -46,6 +46,35 @@ describe("app.helpers.textFormatter", function(){
       })
     });
 
+    context("symbol conversion", function() {
+      beforeEach(function() {
+        this.input_strings = [
+          "->", "<-", "<->",
+          "(c)", "(r)", "(tm)",
+          "<3"
+        ];
+        this.output_symbols = [
+          "→", "←", "↔",
+          "©", "®", "™",
+          "♥"
+        ];
+      });
+
+      it("correctly converts the input strings to their corresponding output symbol", function() {
+        _.each(this.input_strings, function(str, idx) {
+          var text = this.formatter.markdownify(str);
+          expect(text).toContain(this.output_symbols[idx]);
+        }, this);
+      });
+
+      it("converts all symbols at once", function() {
+        var text = this.formatter.markdownify(this.input_strings.join(" "));
+        _.each(this.output_symbols, function(sym) {
+          expect(text).toContain(sym);
+        });
+      });
+    });
+
     context("non-ascii url", function() {
       beforeEach(function() {
         this.evilUrls = [