@servie/events/dist/index.spec.js

Tiny type-safe event emitter

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
const index_1 = require("./index");
describe("events", () => {
    it("should emit events", () => {
        const events = new index_1.Emitter();
        const spy = jest.fn();
        const off = events.on("test", spy);
        events.emit("test", true);
        off();
        events.emit("test", false);
        expect(spy).toHaveBeenCalledTimes(1);
        expect(spy).toHaveBeenLastCalledWith(true);
    });
    it("should remove function only once", () => {
        const events = new index_1.Emitter();
        const spy = jest.fn();
        const off1 = events.on("test", spy);
        const off2 = events.on("test", spy);
        events.emit("test", true);
        expect(spy).toHaveBeenCalledTimes(2);
        expect(off1()).toEqual(true);
        expect(off1()).toEqual(false);
        events.emit("test", true);
        expect(spy).toHaveBeenCalledTimes(3);
        off2();
        events.emit("test", false);
        expect(spy).toHaveBeenCalledTimes(3);
    });
    it("should emit `ALL_EVENTS` event", () => {
        const events = new index_1.Emitter();
        const spy = jest.fn();
        events.emit("test", false);
        expect(spy).not.toHaveBeenCalled();
        const off = events.on(index_1.ALL_EVENTS, spy);
        events.emit("test", true);
        expect(spy).toHaveBeenCalledTimes(1);
        off();
        events.emit("test", false);
        expect(spy).toHaveBeenCalledTimes(1);
    });
    it("should forward `ALL_EVENTS` events easily", () => {
        const events1 = new index_1.Emitter();
        const events2 = new index_1.Emitter();
        const spy = jest.fn();
        events2.on(index_1.ALL_EVENTS, ({ type, args }) => {
            events1.emit(type, ...args);
        });
        events1.on("test", spy);
        events2.emit("test", true);
        expect(spy).toHaveBeenLastCalledWith(true);
    });
    it("should filter `ALL_EVENTS` events easily", () => {
        const events1 = new index_1.Emitter();
        const events2 = new index_1.Emitter();
        const spy = jest.fn();
        events1.on(index_1.ALL_EVENTS, (e) => {
            if (e.type === "test") {
                events2.emit(e.type, ...e.args);
            }
        });
        events2.on("test", spy);
        events1.emit("test", true);
        events1.emit("other", "");
        expect(spy).toHaveBeenLastCalledWith(true);
    });
});
describe("once", () => {
    it("should support a once listener", () => {
        const events = new index_1.Emitter();
        const spy = jest.fn();
        index_1.once(events, "test", spy);
        events.emit("test", true);
        events.emit("test", false);
        expect(spy).toHaveBeenCalledTimes(1);
    });
    it("should not break emitter by removing element within listener", () => {
        const events = new index_1.Emitter();
        const onSpy = jest.fn();
        const onceSpy = jest.fn();
        index_1.once(events, "test", onceSpy);
        events.on("test", onSpy);
        events.emit("test", true);
        expect(onSpy).toHaveBeenCalledTimes(1);
        expect(onceSpy).toHaveBeenCalledTimes(1);
    });
});
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