Don't use JSON for undo state.

Simple deep copies are much faster.

1 files changed, 42 insertions, 14 deletions

diff --git a/rules.js b/rules.js
index a0175cc..f950531 100644
--- a/rules.js
+++ b/rules.js
@@ -132,28 +132,54 @@ function remove_from_array(array, item) {
 		array.splice(i, 1)
 }
 
-function clear_undo() {
-	if (game.undo)
-		game.undo.length = 0
-	else
-		game.undo = []
+function deep_copy(original) {
+	if (Array.isArray(original)) {
+		let n = original.length
+		let copy = new Array(n)
+		for (let i = 0; i < n; ++i) {
+			let v = original[i]
+			if (typeof v === "object" && v !== null)
+				copy[i] = deep_copy(v)
+			else
+				copy[i] = v
+		}
+		return copy
+	} else {
+		let copy = {}
+		for (let i in original) {
+			let v = original[i]
+			if (typeof v === "object" && v !== null)
+				copy[i] = deep_copy(v)
+			else
+				copy[i] = v
+		}
+		return copy
+	}
 }
 
 function push_undo() {
-	game.undo.push(JSON.stringify(game, (k,v) => {
-		if (k === 'undo') return 0
-		if (k === 'log') return v.length
-		return v
-	}))
+	let copy = {}
+	for (let k in game) {
+		let v = game[k]
+		if (k === "undo") continue
+		else if (k === "log") v = v.length
+		else if (typeof v === "object" && v !== null) v = deep_copy(v)
+		copy[k] = v
+	}
+	game.undo.push(copy)
 }
 
 function pop_undo() {
-	let undo = game.undo
 	let save_log = game.log
-	game = JSON.parse(undo.pop())
-	game.undo = undo
+	let save_undo = game.undo
+	game = save_undo.pop()
 	save_log.length = game.log
 	game.log = save_log
+	game.undo = save_undo
+}
+
+function clear_undo() {
+	game.undo = []
 }
 
 function gen_action_undo(view) {
@@ -2497,6 +2523,9 @@ states.game_over = {
 exports.setup = function (seed, scenario, options) {
 	game = {
 		seed: seed,
+		log: [],
+		undo: [],
+
 		c_hand: [],
 		p_hand: [],
 		c_card: 0,
@@ -2515,7 +2544,6 @@ exports.setup = function (seed, scenario, options) {
 		attacker: {},
 		main_road: {},
 		reserves: [],
-		log: [],
 	}
 
 	if (options.tournament) {