In addition to
Down the line, you’ll build your own objects, but for now these “built-in” objects are full of useful functionality.
The great thing about objects is that they have methods! Let’s call the
.random() method from the built-in
console.log(Math.random()); // Prints a random number between 0 and 1
In the example above, we called the
.random() method by appending the object name with the dot operator, the name of the method, and opening and closing parentheses. This method returns a random number between 0 (inclusive) and 1 (exclusive).
To generate a random number between 0 and 50, we could multiply this result by 50, like so:
Math.random() * 50;
The example above will likely evaluate to a decimal. To ensure the answer is a whole number, we can take advantage of another useful
Math method called
Math.floor() takes a decimal number, and rounds down to the nearest whole number. You can use
Math.floor() to round down a random number like this:
Math.floor(Math.random() * 50);
In this case:
Math.randomgenerates a random number between 0 and 1.
- We then multiply that number by
50, so now we have a number between 0 and 50.
Math.floor()rounds the number down to the nearest whole number.
If you wanted to see the number printed to the terminal, you would still need to use a
console.log(Math.floor(Math.random() * 50)); // Prints a random whole number between 0 and 50
To see all of the properties and methods on the
Math object, take a look at the documentation here.
Inside of a
console.log(), create a random number with
Math.random(), then multiply it by
Math.floor() to make the output a whole number.
console.log() you wrote in the last step, put the existing
Math.random() * 100 code inside the parentheses of
Math object that returns the smallest integer greater than or equal to a decimal number.
Use this method with the number
43.8. Log the answer to the console.
Number object that checks if a number is an integer.
Put the number
2017 in the parentheses of the method and use
console.log() to print the result.