Avoid copying data on compare page unless it is really necessary

panstromek · panstromek · commit 47a6c46afbfe · 2020-01-28T19:59:08.000+01:00
diff --git a/site/static/compare.html b/site/static/compare.html
@@ -115,8 +115,16 @@ <h3>Brief explanation</h3>
{
 let filter = document.querySelector("#filter").value;
 let test_names = unique([...Object.keys(data.a.data), ...Object.keys(data.b.data)]);
+ let isCopied = false
 for (let name of test_names){
 if (!name.includes(filter)){
+ if(!isCopied){
+ // Copying data is very expensive
+ // This branch ensures that we avoid copying
+ // if there are no filters (which is the most common case)
+ data = JSON.parse(JSON.stringify(DATA)); // deep copy
+ isCopied = true
+ }
 delete data.a.data[name];
 delete data.b.data[name];
 }
@@ -331,7 +339,6 @@ <h3>Brief explanation</h3>
 }, state);
 make_request("/get", values).then(function(data){
 DATA = data;
- data = JSON.parse(JSON.stringify(DATA)); // deep copy
 populate_data(data);
 });
 }
@@ -350,8 +357,7 @@ <h3>Brief explanation</h3>
 load_state(make_data);
 
 function rerender(){
- let data = JSON.parse(JSON.stringify(DATA)); // deep copy
- populate_data(data);
+ populate_data(DATA);
 }
 
 document.querySelector("#filter").addEventListener("change", rerender);

-Original file line number
+Diff line change
+{
 letfilter=document.querySelector("#filter").value;
 lettest_names=unique([...Object.keys(data.a.data), ...Object.keys(data.b.data)]);
 +letisCopied=false
 for(letnameoftest_names){
 if(!name.includes(filter)){
 +if(!isCopied){
 +// Copying data is very expensive
 +// This branch ensures that we avoid copying
 +// if there are no filters (which is the most common case)
 +data=JSON.parse(JSON.stringify(DATA));// deep copy
 +isCopied=true
 +}
 deletedata.a.data[name];
 deletedata.b.data[name];
+}
 },state);
 make_request("/get",values).then(function(data){
 DATA=data;
 -data=JSON.parse(JSON.stringify(DATA));// deep copy
 populate_data(data);
 });
+}
 load_state(make_data);
 functionrerender(){
 -letdata=JSON.parse(JSON.stringify(DATA));// deep copy
 -populate_data(data);
 +populate_data(DATA);
+}
 document.querySelector("#filter").addEventListener("change",rerender);