JavaScript how to make or

Learn how to use JavaScript to create an interactive example with this step-by-step guide.

Using JavaScript for Or Operations

In JavaScript, the logical OR operator (||) is used to return the first truthy value from the provided arguments. If all arguments provided are falsey, then the last argument is returned. The logical OR operator can be used to set a default value when a variable is undefined or null.

For example, if we want to set the default value of a variable to 'Unknown', we can use the following code:

let name;
let displayName = name || 'Unknown';
console.log(displayName); // Outputs 'Unknown'

We can also use the logical OR operator to combine two conditions. If the first condition is truthy, the second condition is not evaluated. This can be useful to prevent errors from occurring. For example:

let userInput;
let message = userInput || 'Please enter a value';
console.log(message); // Outputs 'Please enter a value'

The logical OR operator can also be used to check if a value is included in an array. For example:

let arr = [1, 2, 3];
let includes2 = arr.includes(2) || false;
console.log(includes2); // Outputs true

In summary, the logical OR operator (||) is a powerful tool in JavaScript that can be used to set default values, combine two conditions, and check if a value is included in an array.