elsint of tree demos

Author: linev

demo/node/tree_draw.js

@@ -10,20 +10,19 @@ let arg = 'https://root.cern/js/files/hsimple.root';
 if (process.argv && (process.argv[2] == 'buf'))
    arg = await httpRequest(arg, 'buf');
 
-const file = await openFile(arg);
-
 // now read ntuple, perform Draw operation, create SVG file and save to the disk
-const ntuple = await file.readObject('ntuple');
-const hist = await treeDraw(ntuple, 'px:py::pz>5');
+const file = await openFile(arg),
+      ntuple = await file.readObject('ntuple'),
+      hist = await treeDraw(ntuple, 'px:py::pz>5');
 hist.fTitle = 'Example of TTree::Draw';
 const svg = await makeSVG({ object: hist, width: 1200, height: 800 });
 writeFileSync('tree_draw1.svg', svg);
 console.log(`Create tree_draw1.svg size ${svg.length}`);
 
 // extract entries list which corresponds to cut expression
-const elist = await treeDraw(ntuple, '::pz>5>>elist');
-// apply entries list for draw expression
-const hist2 = await treeDraw(ntuple, { expr: 'px:py', elist });
+// and apply entries list for draw expression
+const elist = await treeDraw(ntuple, '::pz>5>>elist'),
+      hist2 = await treeDraw(ntuple, { expr: 'px:py', elist });
 hist2.fTitle = 'Example of TTree::Draw';
 const svg2 = await makeSVG({ object: hist2, width: 1200, height: 800 });
 writeFileSync('tree_draw2.svg', svg2);
@@ -46,4 +45,4 @@ if (svg !== svg3)
    console.error('FAILURE: svg and svg3 do not match');
 
 if ((svg === svg2) && (svg2 === svg3))
-   console.log('OK: all svg files match!')
+   console.log('OK: all svg files match!');

demo/node/tree_dump.js

@@ -1,8 +1,8 @@
 import { openFile, treeDraw } from 'jsroot';
 
-let f = await openFile('https://root.cern/js/files/hsimple.root');
-let tree = await f.readObject('ntuple;1');
-let dump = await treeDraw(tree, { expr: 'px:py:pz', dump: true, numentries: 1000 });
+const f = await openFile('https://root.cern/js/files/hsimple.root'),
+      tree = await f.readObject('ntuple;1'),
+      dump = await treeDraw(tree, { expr: 'px:py:pz', dump: true, numentries: 1000 });
 
 console.log(`NumEntries ${dump.length}`);
 let sumx = 0, sumy = 0, sumz = 0;
@@ -13,6 +13,6 @@ dump.forEach(entry => {
    sumz += entry.z;
 });
 
-console.log(`Mean x = ${sumx/dump.length}`);
-console.log(`Mean y = ${sumy/dump.length}`);
-console.log(`Mean z = ${sumz/dump.length}`);
+console.log(`Mean x = ${sumx / dump.length}`);
+console.log(`Mean y = ${sumy / dump.length}`);
+console.log(`Mean z = ${sumz / dump.length}`);

demo/node/tree_selector.js

@@ -1,39 +1,42 @@
-import { openFile }  from 'jsroot/io';
-import { TSelector, treeProcess }  from 'jsroot/tree';
+import { openFile } from 'jsroot/io';
+import { TSelector, treeProcess } from 'jsroot/tree';
 
-let selector = new TSelector();
+class TSelectorExample extends TSelector {
 
-selector.addBranch('px');
-selector.addBranch('py');
+   constructor() {
+      super();
+      this.addBranch('px');
+      this.addBranch('py');
 
-let cnt = 0, sumpx = 0, sumpy = 0;
-
-selector.Begin = function() {
-   // function called before reading of TTree starts
-}
-
-selector.Process = function() {
-   // function called for every entry
-   sumpx += this.tgtobj.px;
-   sumpy += this.tgtobj.py;
-   cnt++;
-}
+      this.cnt = this.sumpx = this.sumpy = 0;
+   }
 
-selector.Terminate = function(res) {
-   // function called when processing finishes
-   if (!res || (cnt === 0)) {
-      console.error('Fail to process TTree');
-   } else {
-      let meanpx = sumpx/cnt, meanpy = sumpy/cnt;
-      console.log(`MeanPX = ${meanpx.toFixed(4)}  MeanPY = ${meanpy.toFixed(4)}`);
+   Begin() {
+      // function called before reading of TTree starts
+      console.log('TTree::Process started');
    }
-}
 
+   Process(/* entry */) {
+      // function called for every entry
+      this.sumpx += this.tgtobj.px;
+      this.sumpy += this.tgtobj.py;
+      this.cnt++;
+   }
 
-let file = await openFile('https://root.cern/js/files/hsimple.root');
+   Terminate(res) {
+      // function called when processing finishes
+      if (!res || !this.cnt)
+         console.error('Fail to process TTree');
+      else {
+         const meanpx = this.sumpx / this.cnt, meanpy = this.sumpy / this.cnt;
+         console.log(`MeanPX = ${meanpx.toFixed(4)}  MeanPY = ${meanpy.toFixed(4)}`);
+      }
+      console.log('TTree::Process finished');
+   }
 
-let tree = await file.readObject('ntuple;1');
+}
 
-await treeProcess(tree, selector);
+const file = await openFile('https://root.cern/js/files/hsimple.root'),
+      tree = await file.readObject('ntuple;1');
 
-console.log('TTree::Process finished');
+await treeProcess(tree, new TSelectorExample);

demo/node/tree_staged.js

@@ -1,5 +1,6 @@
 import { version, openFile, treeDraw, treeProcess, TSelector } from 'jsroot';
 
+
 console.log(`JSROOT version ${version}`);
 
 // Macro demonstrates three different methods to produce entries list which match
@@ -18,11 +19,11 @@ function compareArrays(arr1, arr2) {
    return true;
 }
 
-// open file
-const file = await openFile('https://root.cern/js/files/hsimple.root');
+// open file and read ntuple object
+const file = await openFile('https://root.cern/js/files/hsimple.root'),
+      ntuple = await file.readObject('ntuple');
 
-// read ntuple
-const ntuple = await file.readObject('ntuple');
+console.log(`Read ${ntuple.fName} of type ${ntuple._typename}`);
 
 // use treeDraw to extract array of entries which match condition 'pz>5'
 const entries1 = await treeDraw(ntuple, '::pz>5>>elist');
@@ -37,7 +38,7 @@ selector.addBranch('pz');
 selector.Process = function(entry) {
    if (this.tgtobj.pz > 5)
       entries3.push(entry);
-}
+};
 await treeProcess(ntuple, selector);
 console.log('entries3', entries3.length);
 
@@ -70,7 +71,7 @@ const selector2 = new TSelector, pxarr3 = [];
 selector2.addBranch('px');
 selector2.Process = function() {
    pxarr3.push(this.tgtobj.px);
-}
+};
 await treeProcess(ntuple, selector2, { elist: entries3 });
 console.log('pxarr3', pxarr3.length);