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Chrome Console API

Logs

console.assert

const x = 5;
const y = 3;
const reason = 'x is expected to be less than y';

console.assert(x < y, {x, y, reason});

console.count([label])

console.count();
console.count('coffee');
console.count();
console.count();

console.countReset();
console.countReset('coffee');

console.time([label])

console.time();

for (var i = 0; i < 100000; i++) {
  let square = i ** 2;
}

console.timeEnd();

console.trace()

const first = () => { second(); };
const second = () => { third(); };
const third = () => { fourth(); };
const fourth = () => { console.trace(); };

first();

Utilities

_$ Get the last evaluated expression.

$(), $$(), $x()

  • document.querySelector()
  • document.querySelectorAll()
  • document.evaluate()

inspect()

Open the selected element in Elements panel.

getEventListeners()

Returns an object with an array of attached event listeners.

keys() and values()

Same as Object functions with the same name.

monitor(function) and unmonitor(function)

When the function specified is called, a message is logged to the console.

function sum(x, y) {  return x + y;}
monitor(sum);

monitorEvents(object [, events])

monitorEvents(window, "resize");

monitorEvents(window, ["resize", "scroll"])
Event type Corresponding mapped events
mouse “mousedown”, “mouseup”, “click”, “dblclick”, “mousemove”, “mouseover”, “mouseout”, “mousewheel”
key “keydown”, “keyup”, “keypress”, “textInput”
touch “touchstart”, “touchmove”, “touchend”, “touchcancel”
control “resize”, “scroll”, “zoom”, “focus”, “blur”, “select”, “change”, “submit”, “reset” 
monitorEvents($0, "key");

profile([name]) and profileEnd([name])

Starts a JavaScript CPU profiling session with an optional name.