Don't send 404s for unknown opcodes (makes things messier in js console and caching). Use client-side caching to prevent unnecessary fetches.

lib/asm-docs-api.js

@@ -43,15 +43,15 @@ function docHandler(req, res, next) {
     if (staticMaxAgeSecs) {
         res.setHeader('Cache-Control', 'public, max-age=' + staticMaxAgeSecs);
     }
-    if (!info) {
-        return res.status(404).send("Unknown opcode");
-    }
     if (req.accepts(['text', 'json']) == 'json') {
         res.set('Content-Type', 'application/json');
         res.end(JSON.stringify(info));
     } else {
         res.set('Content-Type', 'text/html');
-        res.end(info.html);
+        if (info)
+            res.end(info.html);
+        else
+            res.end("Unknown opcode");
     }
 }
 

static/compiler.js

@@ -555,7 +555,16 @@ define(function (require) {
         return null;
     }
 
+    var opcodeLike = /^[a-zA-Z][a-zA-Z0-9_.]+$/; // at least two characters
     var getAsmInfo = function (opcode) {
+        if (!opcodeLike.exec(opcode)) {
+            return Promise.reject("Not an opcode");
+        }
+        var cacheName = "asm/" + opcode;
+        var cached = Cache.get(cacheName);
+        if (cached) {
+            return cached;
+        }
         var promise = new Promise(function (resolve, reject) {
             $.ajax({
                 type: 'GET',
@@ -563,6 +572,7 @@ define(function (require) {
                 dataType: 'json',  // Expected,
                 contentType: 'text/plain',  // Sent
                 success: function (result) {
+                    Cache.set(cacheName, result);
                     resolve(result);
                 },
                 error: function (result) {
@@ -595,7 +605,7 @@ define(function (require) {
             }
 
             if (this.settings.hoverShowAsmDoc === true) {
-                getAsmInfo(currentWord.word).then(_.bind(function(response) {
+                getAsmInfo(currentWord.word).then(_.bind(function (response) {
                     this.decorations.asmToolTip = {
                         range: e.target.range,
                         options: {