Thanks to inheritance, we can define our own collection type based on arrays: create our own class that will be inherited from Array:
class Team extends Array {
constructor(name, ...members) {
super(...members);
this.name = name;
}
}
Here we assume that the first parameter of the class constructor is the name of the command, and the second – a set of team players, the number of which is not fixed.
Thanks to inheritance from Array, we can treat objects of the Team class as data sets and apply to them all those operations that apply to arrays:
class Team extends Array {
constructor(name, ...members) {
super(...members);
this.name = name;
}
}
// create command object
const barcelona = new Team("Barcelona", "Tom", "Sam", "Bob");
console.log(barcelona); // Team(3) ["Tom", "Sam", "Bob"]
// enumeration of the set
for (const person of barcelona) {
console.log(person);
}
barcelona.push("Tim"); // add one element
console.log(barcelona); // Team(4) ["Tom", "Sam", "Bob", "Tim"]
barcelona.splice(1, 1); // remove the second element
console.log(barcelona); // Team(3) ["Tom", "Bob", "Tim"]
Overriding standard methods
We can override inherited standard array methods.
class Team extends Array {
constructor(name, ...members) {
super(...members);
this.name = name;
}
//override standard push method
push(person) {
if (person !== "admin") super.push(person);
}
}
const snowbars = new Team("Dinamo", "Tom", "Sam", "Bob");
snowbars.push("admin"); // add one element - admin
console.log(snowbars); // Team(3) ["Tom", "Sam", "Bob"]
snowbars.push("Tim"); // add one element - Tim
console.log(snowbars); // Team(4) ["Tom", "Sam", "Bob", "Tim"]