-
Notifications
You must be signed in to change notification settings - Fork 39
Expand file tree
/
Copy pathevent-aggregation.js
More file actions
50 lines (41 loc) · 1.18 KB
/
event-aggregation.js
File metadata and controls
50 lines (41 loc) · 1.18 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
'use strict';
const { EventEmitter } = require('node:events');
class Point {
#x;
#y;
constructor({ x, y }, emitter) {
const errors = Point.validate(x, y);
if (errors.length > 0) {
const cause = new AggregateError(errors, 'Validation');
throw new RangeError('Bad coordinates', { cause });
}
this.#x = x;
this.#y = y;
emitter.on('move', ({ x, y }) => {
this.#x += x;
this.#y += y;
});
emitter.on('clone', (callback) => {
const point = new Point({ x: this.#x, y: this.#y }, emitter);
callback(point);
});
emitter.on('toString', (callback) => {
callback(`(${this.#x}, ${this.#y})`);
});
}
static validate(x, y) {
const errors = [];
if (!Number.isFinite(x)) errors.push(new TypeError(`Invalid x: ${x}`));
if (!Number.isFinite(y)) errors.push(new TypeError(`Invalid y: ${y}`));
return errors;
}
}
// Usage
const emitter = new EventEmitter();
const p1 = new Point({ x: 10, y: 20 }, emitter);
emitter.emit('toString', console.log);
emitter.emit('clone', (c0) => {
emitter.emit('toString', console.log);
emitter.emit('move', { x: -5, y: 10 });
emitter.emit('toString', console.log);
});