JavaScript console assert() Method

JavaScript console.assert() method is “used to write an error message to the console if the assertion is false. If the assertion is true, nothing happens.”

Syntax

console.assert(expression, message)

Parameters

1. expression: It is required, and any expression.
2. message: It is the message to write in the console.

Return value

It returns None.

Example 1: How to Use console.assert() Method

<script>
  const err_msg = "The # is not positive";
 
  for (let number = -2; number <= 2; number++) {
    console.log(`the # is ${number}`);
    console.assert(number >= 0, "%o", { number, err_msg });
  }
</script>

Output

Example 2: Writing an object to the console

let x;
let y = 2;

const obj = {firstname:"Niva", lastname:"Shah"};

console.assert(x + y == 11, obj);

Output

JavaScript console.assert() method tests if the passed argument is a truthy or falsy value.

Browser compatibility

The console.assert() method is supported in all browsers like Internet Explorer, Mozilla Firefox, Microsoft Edge, Google Chrome browser, Safari, and Opera browser.

That’s it.

Krunal

Krunal Lathiya is a seasoned Computer Science expert with over eight years in the tech industry. He boasts deep knowledge in Data Science and Machine Learning. Versed in Python, JavaScript, PHP, R, and Golang. Skilled in frameworks like Angular and React and platforms such as Node.js. His expertise spans both front-end and back-end development. His proficiency in the Python language stands as a testament to his versatility and commitment to the craft.