Mastering Javascript console methods

• console.assert – writes an error message to the console if the assertion is false.

Syntax : console.assert(expression, message)

let x = 10;
console.assert(x<10, 'X is greater or equal to 10');

• console.clear – clears the console.

console.clear();

• console.count – logs the number of times called this method. optionally you can pass a label to count specific method.

console.count();

• console.debug – outputs a message to the web console at the “debug” log level.

Syntax : 
console.debug(obj1 [, obj2, ..., objN]);
console.debug(msg [, subst1, ..., substN]);

• console.dir – displays an interactive list of the properties of the specified JavaScript object.

let x = {model: 'Audi', color: 'white'};
console.dir(x);

• console.error – Outputs an error message to the Web Console.

console.error("test is an test error");

• console.info – outputs an informational message to the Web Console.

console.info("Hello world!");

• console.log – outputs a message to the Web Console. By adding ‘%c’, you can style the output with CSS. Also, if you wrap an object with {}, it will print object name also.

let x = {y: 10};
let z = 'test';

console.log(x, z);
console.log({x});
console.log('this is a test');
console.log('%c Hello world', "color: blue; font-size: 24px;");

• console.warn – Outputs a warning message to the Web Console.

• console.table – displays data as a table

var people = [["John", "Smith"], ["Jane", "Doe"], ["Emily", "Jones"]]
console.table(people);

• console.timer – Starts a timer.

Syntax : console.time(label);

console.time('my timer');

• console.timerLog – Logs the current value of a timer already running.

Syntax : console.timeLog(label);

console.timeLog('my timer');

• console.timeEnd – Stops the given timer.

console.timeEnd('my timer');

• console.trace – outputs a stack trace to the Web Console.

console.trace();

For more info: https://developer.mozilla.org/en-US/docs/Web/API/console