trace JavaScript using v8's --expose-debug-as= option

trace-self.js

#!/usr/bin/env node

// run with `node --expose-debug-as=Debug fileName.js`

// traces all the code run after dummyFunc() invoked
// see v8/src/debug-debugger.js for some of the impl of the API

var debug = Debug.Debug

//------------------------------------------------------------------------------

function dummyFunc() {}

//------------------------------------------------------------------------------

function listener(event, execState, eventData, data) {
    if (event != debug.DebugEvent.Break) return

    var script   = eventData.func().script().name()
    var line     = eventData.sourceLine()
    var col      = eventData.sourceColumn()

    var location = script + ":" + line + ":" + col

    var funcName = eventData.func().name()
    if (funcName != "") {
        location += " " + funcName + "()"
    }

    console.log(location)

    execState.prepareStep(debug.StepAction.StepIn)
}

//------------------------------------------------------------------------------

function doSomething() {
    for (var i=0; i<10; i++) {
        console.log(i)
    }
}

//------------------------------------------------------------------------------

debug.setListener(listener)
debug.setBreakPoint(dummyFunc, 0, 0)
dummyFunc()

doSomething()