What is the "get" keyword before a function in a class?
It means the function is a getter for a property.
To use it, just use it's name as you would any other property:
'use strict'
class Polygon {
constructor(height, width) {
this.height = height;
this.width = width;
}
get area() {
return this.calcArea()
}
calcArea() {
return this.height * this.width;
}
}
var p = new Polygon(10, 20);
alert(p.area);Summary:
The get keyword will bind an object property to a function. When this property is looked up now the getter function is called. The return value of the getter function then determines which property is returned.
Example:
const person = {
firstName: 'Willem',
lastName: 'Veen',
get fullName() {
return `${this.firstName} ${this.lastName}`;
}
}
console.log(person.fullName);
// When the fullname property gets looked up
// the getter function gets executed and its
// returned value will be the value of fullnameIt is getter, same as Objects and Classes in OO JavaScript. From the MDN Docs for get:
The
getsyntax binds an object property to a function that will be called when that property is looked up.