[geary/wip/794700-lazy-load-conversations: 1/19] Only collapse runs of space, tab, carriage return, and newline

[Michael Gratton <mjog src gnome org>]

commit d5969fde9fd8651a6c039c5833be4d875ca541ef
Author: Alex Henrie <alexhenrie24 gmail com>
Date:   Mon Jan 14 19:54:14 2019 -0700

    Only collapse runs of space, tab, carriage return, and newline
    
    Closes #184

 test/client/composer/composer-web-view-test.vala | 13 +++++++++++++
 ui/composer-web-view.js                          |  6 ++++--
 2 files changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/test/client/composer/composer-web-view-test.vala 
b/test/client/composer/composer-web-view-test.vala
index 6ad0268b..4bb36939 100644
--- a/test/client/composer/composer-web-view-test.vala
+++ b/test/client/composer/composer-web-view-test.vala
@@ -22,6 +22,7 @@ public class ComposerWebViewTest : ClientWebViewTestCase<ComposerWebView> {
         add_test("get_text_with_nbsp", get_text_with_nbsp);
         add_test("get_text_with_named_link", get_text_with_named_link);
         add_test("get_text_with_url_link", get_text_with_named_link);
+        add_test("get_text_with_surrounding_nbsps", get_text_with_surrounding_nbsps);
     }
 
     public void load_resources() throws Error {
@@ -197,6 +198,18 @@ long, long, long, long, long, long, long, long, long, long,
         }
     }
 
+    public void get_text_with_surrounding_nbsps() throws Error {
+        load_body_fixture("&nbsp;&nbsp;I like my space&nbsp;&nbsp;");
+        this.test_view.get_text.begin((obj, ret) => { async_complete(ret); });
+        try {
+            assert(this.test_view.get_text.end(async_result()) ==
+                   "  I like my space\n\n\n\n");
+        } catch (Error err) {
+            print("Error: %s\n", err.message);
+            assert_not_reached();
+        }
+    }
+
     protected override ComposerWebView set_up_test_view() {
         return new ComposerWebView(this.config);
     }
diff --git a/ui/composer-web-view.js b/ui/composer-web-view.js
index 6425cb61..97f2aa18 100644
--- a/ui/composer-web-view.js
+++ b/ui/composer-web-view.js
@@ -473,8 +473,10 @@ ComposerPageState.htmlToText = function(root) {
                     case 'normal':
                     case 'nowrap':
                     case 'pre-line':
-                        nodeText = nodeText.replace(/\s+/g, " ");
-                        if (nodeText == " " && /\s/.test(text.substr(-1)))
+                        // Only space, tab, carriage return, and newline collapse
+                        // https://www.w3.org/TR/2011/REC-CSS2-20110607/text.html#white-space-model
+                        nodeText = nodeText.replace(/[ \t\r\n]+/g, " ");
+                        if (nodeText == " " && " \t\r\n".includes(text.substr(-1)))
                             break; // There's already whitespace here
                         if (node == root.firstChild)
                             nodeText = nodeText.replace(/^ /, "");