In JavaScript - ECMAScript 2021, you can declare a method or function using the function keyword. Here's an example:
// Declaring a function
function greet(name) {
console.log(Hello, ${name}!);
}
// Invoking the function
greet('John');
In the example above, greet is the name of the function and name is a parameter. When the function is invoked with the greet('John') statement, the name parameter is passed the string value of 'John'.
You can also declare a method as a property of an object using a shorthand method syntax. Here's an example:
// Declaring a method using shorthand method syntax
const person = {
firstName: 'John',
lastName: 'Doe',
greet() {
console.log(Hello, ${this.firstName} ${this.lastName}!);
}
}
// Invoking the method
person.greet();
In the example above, greet is declared as a method of the person object using the shorthand method syntax. A method declared in this way will automatically bind the this keyword to the object the method is called on.