js: Do not unconditionally set gen_update_hook

When we reload, can bust the tests, as the hook gets overwritten.
I think.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/templates/script.ts b/templates/script.ts
index a2db2305cadef73a943dd943882f2bb16e6e41f3..7694abf810577f3d184e37a5f4eaa67a8d8d5073 100644 (file)
--- a/templates/script.ts
+++ b/templates/script.ts
@@ -119,7 +119,7 @@ var keyops_local : { [opname: string]: (uo: UoRecord) => void } = Object();
 var last_log_ts: wasm_bindgen.TimestampAbbreviator;
 var last_zoom_factor : number = 1.0;
 var firefox_bug_zoom_factor_compensation : number = 1.0;
-var gen_update_hook : () => void = function() { }
+var gen_update_hook : () => void;
 
 var svg_ns : string;
 var space : SVGGraphicsElement;
@@ -1450,6 +1450,8 @@ function startup() {
     redisplay_ancillaries(piece,p);
   }
 
+  if (gen_update_hook == null) gen_update_hook = function() { };
+
   last_log_ts = wasm_bindgen.timestamp_abbreviator(dataload.last_log_ts);
 
   var es = new EventSource(