From 5d641bbf24ebe675f919114711fc586758fe27e5 Mon Sep 17 00:00:00 2001
From: David Anson <david@dlaa.me>
Date: Wed, 4 Mar 2015 18:23:19 -0800
Subject: [PATCH] Refactor rules for clarity/brevity.

---
 lib/rules.js | 114 +++++++++++++++++++++++++--------------------------
 1 file changed, 55 insertions(+), 59 deletions(-)

diff --git a/lib/rules.js b/lib/rules.js
index e940f310..f4ad255e 100644
--- a/lib/rules.js
+++ b/lib/rules.js
@@ -1,10 +1,10 @@
 "use strict";
 
-function indentFrom(token) {
+function indentFor(token) {
   return token.line.length - token.line.trimLeft().length;
 }
 
-function headingStyleFrom(token) {
+function headingStyleFor(token) {
   if ((token.lines[1] - token.lines[0]) === 1) {
     if (token.line.match(/#\s*$/)) {
       return "atx_closed";
@@ -14,7 +14,7 @@ function headingStyleFrom(token) {
   return "setext";
 }
 
-function unorderedListStyleFrom(token) {
+function unorderedListStyleFor(token) {
   switch (token.line.trimLeft().substr(0, 1)) {
     case "*":
       return "asterisk";
@@ -27,6 +27,12 @@ function unorderedListStyleFrom(token) {
   }
 }
 
+function filterTokens(tokens, tokenA, tokenB) {
+  return tokens.filter(function filterToken(token) {
+    return ((token.type === tokenA) || (token.type === tokenB));
+  });
+}
+
 function padAndTrim(lines) {
   return [].concat(
     "",
@@ -42,14 +48,13 @@ module.exports = [
     "desc": "Header levels should only increment by one level at a time",
     "func": function MD001(params, errors) {
       var prevLevel = 0;
-      params.tokens.filter(function filterToken(token) {
-        return (token.type === "heading_open");
-      }).forEach(function forToken(token) {
-        if (prevLevel && (token.hLevel > prevLevel + 1)) {
-          errors.push(token.lineNumber);
-        }
-        prevLevel = token.hLevel;
-      });
+      filterTokens(params.tokens, "heading_open")
+        .forEach(function forToken(token) {
+          if (prevLevel && (token.hLevel > prevLevel + 1)) {
+            errors.push(token.lineNumber);
+          }
+          prevLevel = token.hLevel;
+        });
     }
   },
 
@@ -74,14 +79,12 @@ module.exports = [
     "desc": "Header style",
     "func": function MD003(params, errors) {
       var style = params.options.style || "consistent";
-      var headings = params.tokens.filter(function filterToken(token) {
-        return (token.type === "heading_open");
-      });
+      var headings = filterTokens(params.tokens, "heading_open");
       if ((style === "consistent") && headings.length) {
-        style = headingStyleFrom(headings[0]);
+        style = headingStyleFor(headings[0]);
       }
       headings.forEach(function forToken(token) {
-        if (headingStyleFrom(token) !== style) {
+        if (headingStyleFor(token) !== style) {
           errors.push(token.lineNumber);
         }
       });
@@ -93,14 +96,12 @@ module.exports = [
     "desc": "Unordered list style",
     "func": function MD004(params, errors) {
       var style = params.options.style || "consistent";
-      var listItems = params.tokens.filter(function filterToken(token) {
-        return (token.type === "list_item_open");
-      });
+      var listItems = filterTokens(params.tokens, "list_item_open");
       if ((style === "consistent") && listItems.length) {
-        style = unorderedListStyleFrom(listItems[0]);
+        style = unorderedListStyleFor(listItems[0]);
       }
       listItems.forEach(function forToken(token) {
-        if (unorderedListStyleFrom(token) !== style) {
+        if (unorderedListStyleFor(token) !== style) {
           errors.push(token.lineNumber);
         }
       });
@@ -112,16 +113,15 @@ module.exports = [
     "desc": "Inconsistent indentation for list items at the same level",
     "func": function MD005(params, errors) {
       var indentLevels = [];
-      params.tokens.filter(function filterToken(token) {
-        return (token.type === "list_item_open");
-      }).forEach(function forToken(token) {
-        var indentLevel = indentFrom(token);
-        if (!indentLevels[token.level]) {
-          indentLevels[token.level] = indentLevel;
-        } else if (indentLevel !== indentLevels[token.level]) {
-          errors.push(token.lineNumber);
-        }
-      });
+      filterTokens(params.tokens, "list_item_open")
+        .forEach(function forToken(token) {
+          var indentLevel = indentFor(token);
+          if (!indentLevels[token.level]) {
+            indentLevels[token.level] = indentLevel;
+          } else if (indentLevel !== indentLevels[token.level]) {
+            errors.push(token.lineNumber);
+          }
+        });
     }
   },
 
@@ -142,7 +142,7 @@ module.exports = [
             return false;
         }
       }).forEach(function forToken(token) {
-        if (indentFrom(token) !== 0) {
+        if (indentFor(token) !== 0) {
           errors.push(token.lineNumber);
         }
       });
@@ -155,16 +155,15 @@ module.exports = [
     "func": function MD007(params, errors) {
       var optionsIndent = params.options.indent || 2;
       var prevIndent = 0;
-      params.tokens.filter(function filterToken(token) {
-        return (token.type === "bullet_list_open");
-      }).forEach(function forToken(token) {
-        var indent = indentFrom(token);
-        if ((indent > prevIndent) &&
-            ((indent - prevIndent) !== optionsIndent)) {
-          errors.push(token.lineNumber);
-        }
-        prevIndent = indent;
-      });
+      filterTokens(params.tokens, "bullet_list_open")
+        .forEach(function forToken(token) {
+          var indent = indentFor(token);
+          if ((indent > prevIndent) &&
+              ((indent - prevIndent) !== optionsIndent)) {
+            errors.push(token.lineNumber);
+          }
+          prevIndent = indent;
+        });
     }
   },
 
@@ -198,17 +197,15 @@ module.exports = [
     "name": "MD011",
     "desc": "Reversed link syntax",
     "func": function MD011(params, errors) {
-      params.tokens.filter(function filterToken(token) {
-        return (token.type === "inline");
-      }).forEach(function forToken(token) {
-        token.children.filter(function filterChild(child) {
-          return (child.type === "text");
-        }).forEach(function forChild(child) {
-          if (child.content.match(/\([^)]+\)\[[^\]]+\]/)) {
-            errors.push(token.lineNumber);
-          }
+      filterTokens(params.tokens, "inline")
+        .forEach(function forToken(token) {
+          filterTokens(token.children, "text")
+            .forEach(function forChild(child) {
+              if (child.content.match(/\([^)]+\)\[[^\]]+\]/)) {
+                errors.push(token.lineNumber);
+              }
+            });
         });
-      });
     }
   },
 
@@ -217,13 +214,12 @@ module.exports = [
     "desc": "Multiple consecutive blank lines",
     "func": function MD012(params, errors) {
       var exclusions = [];
-      params.tokens.filter(function filterToken(token) {
-        return ((token.type === "code_block") || (token.type === "fence"));
-      }).forEach(function forToken(token) {
-        for (var i = token.lines[0] ; i < token.lines[1] ; i++) {
-          exclusions.push(i);
-        }
-      });
+      filterTokens(params.tokens, "code_block", "fence")
+        .forEach(function forToken(token) {
+          for (var i = token.lines[0] ; i < token.lines[1] ; i++) {
+            exclusions.push(i);
+          }
+        });
       var prevLine = "-";
       params.lines.forEach(function forLine(line, lineIndex) {
         line = line.trim();