optimize rule lookup

we have tons of bbcode rules, might as well speed them up

app/assets/javascripts/pretty-text/engines/discourse-markdown-it.js.es6

@@ -48,8 +48,24 @@ class Ruler {
     return this.rules;
   }
 
+  getRuleForTag(tag) {
+    this.ensureCache();
+    return this.cache[tag];
+  }
+
+  ensureCache() {
+    if (this.cache) { return; }
+
+    this.cache = {};
+    for(let i=this.rules.length-1;i>=0;i--) {
+      let info = this.rules[i];
+      this.cache[info.rule.tag] = info;
+    }
+  }
+
   push(name, rule) {
     this.rules.push({name, rule});
+    this.cache = null;
   }
 }
 

app/assets/javascripts/pretty-text/engines/markdown-it/bbcode-block.js.es6

@@ -111,7 +111,7 @@ export function parseBBCodeTag(src, start, max, multiline) {
 
 function applyBBCode(state, startLine, endLine, silent, md) {
 
-  var i, nextLine,
+  var nextLine,
       old_parent, old_line_max, rule,
       start = state.bMarks[startLine] + state.tShift[startLine],
       initial = start,
@@ -126,18 +126,10 @@ function applyBBCode(state, startLine, endLine, silent, md) {
     return false;
   }
 
-  let rules = md.block.bbcode_ruler.getRules();
+  let ruleInfo = md.block.bbcode_ruler.getRuleForTag(info.tag);
+  if (!ruleInfo) { return false; }
 
-  for(i=0;i<rules.length;i++) {
-    let r = rules[i].rule;
-
-    if (r.tag === info.tag) {
-      rule = r;
-      break;
-    }
-  }
-
-  if (!rule) { return false; }
+  rule = ruleInfo.rule;
 
   // Since start is found, we can report success here in validation mode
   if (silent) { return true; }

app/assets/javascripts/pretty-text/engines/markdown-it/bbcode-inline.js.es6

@@ -15,20 +15,12 @@ function tokanizeBBCode(state, silent, ruler) {
     return false;
   }
 
-  let rules = ruler.getRules();
   let rule, i;
 
-  for (i=0; i<rules.length; i++) {
-    let r = rules[i].rule;
-    if (r.tag === tagInfo.tag) {
-      rule = r;
-      break;
-    }
-  }
+  let ruleInfo = ruler.getRuleForTag(tagInfo.tag);
+  if (!ruleInfo) { return false; }
+  rule = ruleInfo.rule;
 
-  if (!rule) {
-    return false;
-  }
 
   if (rule.replace) {
     // special handling for replace