fondue
Collect real-time JavaScript traces (number of times a function has been called, locations where exceptions have been thrown, etc).
Easily instrument an entire program with node-theseus.
Plain objects are returned from all API calls so that they can be passed around as JSON. node-theseus does this with a WebSocket. Theseus does it over Chrome's Remote Debugging API (which boils down to a WebSocket).
Install
npm install fondue
Documentation
http://adobe-research.github.io/fondue/
Use
Execute instrumented code:
var fondue = require('fondue'),
vm = require('vm');
var src = fondue.instrument('function foo(a) { return a * 2 }; foo(4)');
var sandbox = { __tracer: undefined, console: console, require: require };
var output = vm.runInNewContext(src, sandbox);
var tracer = sandbox.__tracer; // created by fondue when instrumented code is runTrack trace points (functions, call sites, etc):
var functions = {};
var nodesHandle = tracer.trackNodes();
tracer.newNodes(nodesHandle).forEach(function (n) {
if (n.type === 'function') {
functions[n.name] = n;
}
});
var fooNode = functions['foo'];
console.log('foo started at', fooNode.start, 'and ended at', fooNode.end);
// call tracer.newNodes() periodically if you expect new code to be required over timeTrack hit counts:
// check how many times trace points have been hit
var hitsHandle = tracer.trackHits();
var hits1 = tracer.hitCountDeltas(hitsHandle);
console.log('foo was called ' + (hits1[fooNode.id] || 0) + ' time');
// call repeatedly to track hit counts over time
var hits2 = tracer.hitCountDeltas(hitsHandle);
console.log('foo was called ' + (hits2[fooNode.id] || 0) + ' times (since last check)');Access function arguments and return values (and unhandled exceptions):
var logHandle = tracer.trackLogs({ ids: [fooNode.id] });
var invocations = tracer.logDelta(logHandle);
console.log('foo returned:', invocations[0].returnValue);
console.log('foo accepted arguments:', invocations[0].arguments);