v1.5.1 release candidate (#353)

* Use  to schedule staticRender() iff jQuery 3 or higher is present in shinyMode

* Bump version; update NEWS

* Prevent staticRender from being called unconditionally when htmlwidgets.js is loaded after page load

* Add a comment; abstract out duplication in logic (#354)

DESCRIPTION

@@ -1,7 +1,7 @@
 Package: htmlwidgets
 Type: Package
 Title: HTML Widgets for R
-Version: 1.5.0.9000
+Version: 1.5.1
 Authors@R: c(
     person("Ramnath", "Vaidyanathan", role = c("aut", "cph")),
     person("Yihui", "Xie", role = c("aut")),

inst/NEWS

@@ -1,3 +1,8 @@
+htmlwidgets 1.5.1
+-------------------------------------------------------
+
+* Fixed an issue with dynamically rendered widgets (i.e., using `shiny::uiOutput()` to render a widget) with any version of shiny prior to 1.4. This issue was introduced by htmlwidgets 1.5. (#351)
+
 htmlwidgets 1.5
 -----------------------------------------------------------------------
 

inst/www/htmlwidgets.js

@@ -659,44 +659,56 @@
     invokePostRenderHandlers();
   }
 
-  // Wait until after the document has loaded to render the widgets.
-  if (shinyMode && window.jQuery) {
-    /*
-    / Shiny 1.4.0 bumps jQuery from 1.x to 3.x, which means jQuery's
-    / on-ready handler (i.e., $(fn)) is now asyncronous (i.e., it now
-    / really means $(setTimeout(fn)). https://jquery.com/upgrade-guide/3.0/#breaking-change-document-ready-handlers-are-now-asynchronous
-    /
-    / In order to ensure the order of execution of on-ready handlers
-    / remains consistent with how it's been in the past, a static render
-    / in Shiny is now scheduled via $().
-    /
-    / This is not a long term solution: it just preserves the current order
-    / of execution. Part of that ordering is to ensure initShiny executes
-    / _after_ staticRender, which is both right and wrong:
-    / * It's wrong because, when initShiny executes, it registers methods
-    / like Shiny.onInputChange that widget authors would expect to be available
-    / during a staticRender.
-    / * It's also 'right' because initShiny currently (as of v1.4.0) wants
-    / to execute after user code so that it can bind to any dynamically
-    / created elements.
-    /
-    / A longer term solution might be to make changes to Shiny so that
-    / these methods are available before the binding takes place, and then
-    / the ordering would be: register methods -> static render -> bind.
-    */
-    window.jQuery(function() {
+
+  function has_jQuery3() {
+    if (!window.jQuery) {
+      return false;
+    }
+    var $version = window.jQuery.fn.jquery;
+    var $major_version = parseInt($version.split(".")[0]);
+    return $major_version >= 3;
+  }
+
+  /*
+  / Shiny 1.4 bumped jQuery from 1.x to 3.x which means jQuery's
+  / on-ready handler (i.e., $(fn)) is now asyncronous (i.e., it now
+  / really means $(setTimeout(fn)).
+  / https://jquery.com/upgrade-guide/3.0/#breaking-change-document-ready-handlers-are-now-asynchronous
+  /
+  / Since Shiny uses $() to schedule initShiny, shiny>=1.4 calls initShiny
+  / one tick later than it did before, which means staticRender() is
+  / called renderValue() earlier than (advanced) widget authors might be expecting.
+  / https://github.com/rstudio/shiny/issues/2630
+  /
+  / For a concrete example, leaflet has some methods (e.g., updateBounds)
+  / which reference Shiny methods registered in initShiny (e.g., setInputValue).
+  / Since leaflet is privy to this life-cycle, it knows to use setTimeout() to
+  / delay execution of those methods (until Shiny methods are ready)
+  / https://github.com/rstudio/leaflet/blob/18ec981/javascript/src/index.js#L266-L268
+  /
+  / Ideally widget authors wouldn't need to use this setTimeout() hack that
+  / leaflet uses to call Shiny methods on a staticRender(). In the long run,
+  / the logic initShiny should be broken up so that method registration happens
+  / right away, but binding happens later.
+  */
+  function maybeStaticRenderLater() {
+    if (shinyMode && has_jQuery3()) {
+      window.jQuery(window.HTMLWidgets.staticRender);
+    } else {
       window.HTMLWidgets.staticRender();
-    });
-  } else if (document.addEventListener) {
+    }
+  }
+
+  if (document.addEventListener) {
     document.addEventListener("DOMContentLoaded", function() {
       document.removeEventListener("DOMContentLoaded", arguments.callee, false);
-      window.HTMLWidgets.staticRender();
+      maybeStaticRenderLater();
     }, false);
   } else if (document.attachEvent) {
     document.attachEvent("onreadystatechange", function() {
       if (document.readyState === "complete") {
         document.detachEvent("onreadystatechange", arguments.callee);
-        window.HTMLWidgets.staticRender();
+        maybeStaticRenderLater();
       }
     });
   }