eslint/tests/lib/linter/safe-emitter.js

   1 /**
   2  * @fileoverview Tests for safe-emitter
   3  * @author Teddy Katz
   4  */
   5
   6 "use strict";
   7
   8 const createEmitter = require("../../../lib/linter/safe-emitter");
   9 const assert = require("chai").assert;
  10
  11 describe("safe-emitter", () => {
  12     describe("emit() and on()", () => {
  13         it("allows listeners to be registered calls them when emitted", () => {
  14             const emitter = createEmitter();
  15             const colors = [];
  16
  17             emitter.on("foo", () => colors.push("red"));
  18             emitter.on("foo", () => colors.push("blue"));
  19             emitter.on("bar", () => colors.push("green"));
  20
  21             emitter.emit("foo");
  22             assert.deepStrictEqual(colors, ["red", "blue"]);
  23
  24             emitter.on("bar", color => colors.push(color));
  25             emitter.emit("bar", "yellow");
  26
  27             assert.deepStrictEqual(colors, ["red", "blue", "green", "yellow"]);
  28         });
  29
  30         it("calls listeners with no `this` value", () => {
  31             const emitter = createEmitter();
  32             let called = false;
  33
  34             emitter.on("foo", function() {
  35                 assert.strictEqual(this, void 0); // eslint-disable-line no-invalid-this
  36                 called = true;
  37             });
  38
  39             emitter.emit("foo");
  40             assert(called);
  41         });
  42     });
  43 });