From: Jason Woofenden <jason@jasonwoof.com>
Date: Wed, 30 Mar 2016 14:54:37 +0000 (-0400)
Subject: optimize whitespace dedup
X-Git-Url: https://jasonwoof.com/gitweb/?p=peach-html5-editor.git;a=commitdiff_plain;h=30aee05f9c37a3954f5f849823b2e84a304423ff

optimize whitespace dedup
---

diff --git a/editor.coffee b/editor.coffee
index a0bd0a4..dd39c62 100644
--- a/editor.coffee
+++ b/editor.coffee
@@ -559,21 +559,32 @@ tree_dedup_space = (tree) ->
 					throw "how is this possible?"
 				next_i -= 1
 			return 1
-	whitespace_to_space = (undo) ->
+	replace_with_space = (undo) ->
 		if undo
 			cur.text = (cur.text.substr 0, cur_i) + removed_char + (cur.text.substr cur_i + 1)
 			cur.el.textContent = cur.text
 		else
 			removed_char = cur.text.charAt(cur_i)
-			cur.text = (cur.text.substr 0, cur_i) + ' ' + (cur.text.substr cur_i + 1)
-			cur.el.textContent = cur.text
+			if removed_char isnt ' '
+				cur.text = (cur.text.substr 0, cur_i) + ' ' + (cur.text.substr cur_i + 1)
+				cur.el.textContent = cur.text
 		return 0
 	# return true if cur was removed from the dom (ie re-use same prev)
 	operate = ->
 		# cur definitately set
 		# prev and/or next might be null, indicating the start/end of a display:block
 		return false unless is_space_code cur.text.charCodeAt cur_i
-		fixers = [remove, whitespace_to_space]
+		fixers = [remove, replace_with_space]
+		# check for common case: single whitespace surrounded by non-whitespace chars
+		if prev? and next?
+			unless (is_space_code prev.text.charCodeAt prev_i) or (is_space_code next.text.charCodeAt next_i)
+				dbg = cur.text.charCodeAt cur_i
+				if cur.text.charAt(cur_i) is ' ' # perens required
+					# single space can't collapse, doesn't need fixin'
+					return false
+				else
+					# tab, newline, etc, can't collapse, but maybe should be replaced
+					fixers = [replace_with_space]
 		bounds = text_range_bounds cur.el, cur_i, cur_i + 1
 		# consistent cases:
 		# 1. zero rects returned by getClientRects() means collapsed space
@@ -581,7 +592,8 @@ tree_dedup_space = (tree) ->
 			return remove()
 		# 2. width greater than zero means visible space
 		if bounds.w > 0
-			fixers.shift() # don't try removing
+			# has bounds, don't try removing
+			fixers = [replace_with_space]
 		# now the weird edge cases...
 		#
 		# firefox and chromium both report zero width for characters at the end
@@ -590,6 +602,11 @@ tree_dedup_space = (tree) ->
 		# collapsed spaces via the range/bounds api, so...
 		#
 		# remove it from the dom, and if prev or next moves, put it back.
+		#
+		# this block (try changing it, put it back if something moves) is also
+		# used on collapsable whitespace characters besides space. In this case
+		# the character is replaced with a normal space character instead of
+		# removed
 		if prev? and not prev_px?
 			prev_px = new_cursor_position n: prev, i: prev_i
 		if next? and not next_px?