add perf tester to global scope in test dashboard

Author: alexcjohnson

devtools/test_dashboard/devtools.js

@@ -8,6 +8,8 @@ var credentials = require('../../build/credentials.json');
 var Lib = require('@src/lib');
 var d3 = Plotly.d3;
 
+require('./perf');
+
 // Our gracious testing object
 var Tabs = {
 

devtools/test_dashboard/perf.js

@@ -0,0 +1,54 @@
+'use strict';
+
+/*
+ * timeit: tool for performance testing
+ * f: function to be tested
+ * n: number of timing runs
+ * nchunk: optional number of repetitions per timing run - useful if
+ *   the function is very fast. Note though that if arg is a function
+ *   it will not be re-evaluated within the chunk, only before each chunk.
+ * arg: optional argument to the function. Can be a function itself
+ *   to provide a changing input to f
+ */
+window.timeit = function(f, n, nchunk, arg) {
+    var times = new Array(n);
+    var totalTime = 0;
+    var _arg;
+    var t0, t1, dt;
+
+    for(var i = 0; i < n; i++) {
+        if(typeof arg === 'function') _arg = arg();
+        else _arg = arg;
+
+        if(nchunk) {
+            t0 = performance.now();
+            for(var j = 0; j < nchunk; j++) { f(_arg); }
+            t1 = performance.now();
+            dt = (t1 - t0) / nchunk;
+        }
+        else {
+            t0 = performance.now();
+            f(_arg);
+            t1 = performance.now();
+            dt = t1 - t0;
+        }
+
+        times[i] = dt;
+        totalTime += dt;
+    }
+
+    var first = (times[0]).toFixed(4);
+    var last = (times[n - 1]).toFixed(4);
+    times.sort();
+    var min = (times[0]).toFixed(4);
+    var max = (times[n - 1]).toFixed(4);
+    var median = (times[Math.ceil(n / 2)]).toFixed(4);
+    var mean = (totalTime / n).toFixed(4);
+    console.log((f.name || 'function') + ' timing (ms) - min: ' + min +
+        '  max: ' + max +
+        '  median: ' + median +
+        '  mean: ' + mean +
+        '  first: ' + first +
+        '  last: ' + last
+    );
+};