🚴 perf(DeepIterator): Replace instanceof checks by proto.

Author: make-github-pseudonymous-again

src/0-core/_fast/fast-iterators/BackwardIterator.js

@@ -29,14 +29,7 @@ BackwardIterator.prototype._upwardStep = function () {
 };
 
 BackwardIterator.prototype._traverse = function (level, x) {
-	if (x instanceof Node3) {
-		this._level.push(level, level);
-		this._stack.push(x.a, x.b);
-		return x.c;
-	}
-
-	assert(x instanceof Node2);
-	this._level.push(level);
-	this._stack.push(x.a);
-	return x.b;
+	assert(Number.isInteger(level) && level >= 0);
+	assert(x instanceof Node2 || x instanceof Node3);
+	return x._backward(level, this);
 };

src/0-core/_fast/fast-iterators/ForwardIterator.js

@@ -29,14 +29,7 @@ ForwardIterator.prototype._upwardStep = function () {
 };
 
 ForwardIterator.prototype._traverse = function (level, x) {
-	if (x instanceof Node3) {
-		this._level.push(level, level);
-		this._stack.push(x.c, x.b);
-		return x.a;
-	}
-
-	assert(x instanceof Node2);
-	this._level.push(level);
-	this._stack.push(x.b);
-	return x.a;
+	assert(Number.isInteger(level) && level >= 0);
+	assert(x instanceof Node2 || x instanceof Node3);
+	return x._forward(level, this);
 };

src/2-node/2-Node2.js

@@ -13,3 +13,15 @@ Node2.prototype.measure = function () {
 Node2.prototype._digit = function () {
 	return new Two(this.a, this.b);
 };
+
+Node2.prototype._forward = function (level, iterator) {
+	iterator._level.push(level);
+	iterator._stack.push(this.b);
+	return this.a;
+};
+
+Node2.prototype._backward = function (level, iterator) {
+	iterator._level.push(level);
+	iterator._stack.push(this.a);
+	return this.b;
+};

src/2-node/3-Node3.js

@@ -14,3 +14,15 @@ Node3.prototype.measure = function () {
 Node3.prototype._digit = function () {
 	return new Three(this.a, this.b, this.c);
 };
+
+Node3.prototype._forward = function (level, iterator) {
+	iterator._level.push(level, level);
+	iterator._stack.push(this.c, this.b);
+	return this.a;
+};
+
+Node3.prototype._backward = function (level, iterator) {
+	iterator._level.push(level, level);
+	iterator._stack.push(this.a, this.b);
+	return this.c;
+};