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javascriptlambdagoogle-chrome-devtoolsbreakpointssource-maps

How to set a breakpoint at a lambda call in Google Chrome DevTools?


I use Babel and Google Chrome Developer Tools with JavaScript source maps enabled. Given this code

function myFunc(elements) {
  return elements
    .map(element => element.value)
    .filter(value => value >= 0);
}

how can I pause execution at execution of lambda function element => element.value? If I set a breakpoint at line of .map(element => element.value) it will only pause when map is executed, but not when the lambda function is executed.


Solution

  • This feature is finally available (at least in Google Chrome 58). Click on the line number of the line of your lambda you like to debug (here line 3). Then activate the marker in your lambda (here the second) by clicking it. Further, I disabled the first marker here, which would pause on the map call (not the lambda):

    Set breakpoint

    When your program runs and hits the breakpoint, it will pause and you can inspect variables:

    Paused on breakpoint