more chain method improvements.

lib/bcoin/chain.js

@@ -383,7 +383,10 @@ Chain.prototype.has = function has(hash, noProbe, cb) {
     return cb(true);
   }
 
-  return cb(!!this.orphan.map[hash]);
+  if (this.hasOrphan(hash))
+    return cb(true);
+
+  return cb(false);
 };
 
 Chain.prototype.byHeight = function byHeight(height) {
@@ -480,9 +483,13 @@ Chain.prototype.get = function get(hash, force, cb) {
         return;
       }
     }
-    assert(false);
+    // False positive:
+    // assert(false);
   }
 
+  if (!force && this.orphan.bmap[hash])
+    return cb(this.orphan.bmap[hash]);
+
   if (this.request.add(hash, cb))
     this.emit('missing', hash, null, null);
 };

lib/bcoin/fullchain.js

@@ -249,8 +249,6 @@ Chain.prototype.add = function add(block) {
 };
 
 Chain.prototype.has = function has(hash, noProbe, cb) {
-  var res;
-
   if (typeof noProbe === 'function') {
     cb = noProbe;
     noProbe = false;
@@ -263,13 +261,11 @@ Chain.prototype.has = function has(hash, noProbe, cb) {
     return;
   }
 
-  res = this.hasBlock(hash) || this.hasOrphan(hash);
-
-  if (!cb)
-    return res;
-
   cb = utils.asyncify(cb);
-  return cb(res);
+
+  assert(!noProbe);
+
+  return cb(this.hasBlock(hash) || this.hasOrphan(hash));
 };
 
 Chain.prototype.byHeight = function byHeight(height) {
@@ -338,22 +334,14 @@ Chain.prototype.hashesInRange = function hashesInRange(start, end, cb) {
 };
 
 Chain.prototype.getLast = function getLast(cb) {
-  var res;
-
   if (this.loading) {
     this.once('load', function() {
       this.getLast(cb);
     });
     return;
   }
-
-  res = this.index.hashes[this.index.hashes.length - 1];
-
-  if (!cb)
-    return res;
-
   cb = utils.asyncify(cb);
-  return cb(res);
+  return cb(this.index.hashes[this.index.hashes.length - 1]);
 };
 
 Chain.prototype.getStartHeight = function getStartHeight() {