From 1b13bac9071380fedca0179372e9c8341b5b0546 Mon Sep 17 00:00:00 2001 From: Jeff Williams Date: Sun, 27 Jan 2019 13:33:21 -0800 Subject: [PATCH] add `@jsdoc/bus` package (currently unused) --- package-lock.json | 6 +- package.json | 1 + packages/jsdoc-bus/LICENSE | 174 +++++++++++++++++++++++ packages/jsdoc-bus/README.md | 11 ++ packages/jsdoc-bus/index.js | 3 + packages/jsdoc-bus/lib/bus.js | 50 +++++++ packages/jsdoc-bus/package.json | 22 +++ packages/jsdoc-bus/test/specs/index.js | 12 ++ packages/jsdoc-bus/test/specs/lib/bus.js | 66 +++++++++ 9 files changed, 344 insertions(+), 1 deletion(-) create mode 100644 packages/jsdoc-bus/LICENSE create mode 100644 packages/jsdoc-bus/README.md create mode 100644 packages/jsdoc-bus/index.js create mode 100644 packages/jsdoc-bus/lib/bus.js create mode 100644 packages/jsdoc-bus/package.json create mode 100644 packages/jsdoc-bus/test/specs/index.js create mode 100644 packages/jsdoc-bus/test/specs/lib/bus.js diff --git a/package-lock.json b/package-lock.json index c33cd4e1..74ae0f53 100644 --- a/package-lock.json +++ b/package-lock.json @@ -127,6 +127,9 @@ "to-fast-properties": "^2.0.0" } }, + "@jsdoc/bus": { + "version": "file:packages/jsdoc-bus" + }, "@jsdoc/cli": { "version": "file:packages/jsdoc-cli", "requires": { @@ -356,7 +359,8 @@ "@jsdoc/util": { "version": "file:packages/jsdoc-util", "requires": { - "klaw-sync": "^6.0.0" + "klaw-sync": "^6.0.0", + "lodash": "^4.17.11" } }, "@lerna/add": { diff --git a/package.json b/package.json index 9a1662c3..f5ec1615 100644 --- a/package.json +++ b/package.json @@ -14,6 +14,7 @@ }, "dependencies": { "@babel/parser": "~7.2.3", + "@jsdoc/bus": "file:packages/jsdoc-bus", "@jsdoc/cli": "file:packages/jsdoc-cli", "@jsdoc/config": "file:packages/jsdoc-config", "@jsdoc/logger": "file:packages/jsdoc-logger", diff --git a/packages/jsdoc-bus/LICENSE b/packages/jsdoc-bus/LICENSE new file mode 100644 index 00000000..dd5b3a58 --- /dev/null +++ b/packages/jsdoc-bus/LICENSE @@ -0,0 +1,174 @@ + Apache License + Version 2.0, January 2004 + http://www.apache.org/licenses/ + + TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION + + 1. 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However, in accepting such obligations, You may act only + on Your own behalf and on Your sole responsibility, not on behalf + of any other Contributor, and only if You agree to indemnify, + defend, and hold each Contributor harmless for any liability + incurred by, or claims asserted against, such Contributor by reason + of your accepting any such warranty or additional liability. diff --git a/packages/jsdoc-bus/README.md b/packages/jsdoc-bus/README.md new file mode 100644 index 00000000..6c2350fc --- /dev/null +++ b/packages/jsdoc-bus/README.md @@ -0,0 +1,11 @@ +# @jsdoc/bus + +An event bus with no dependencies. + +## Installing the package + +Using npm: + +```shell +npm install --save @jsdoc/bus +``` diff --git a/packages/jsdoc-bus/index.js b/packages/jsdoc-bus/index.js new file mode 100644 index 00000000..7f66abcd --- /dev/null +++ b/packages/jsdoc-bus/index.js @@ -0,0 +1,3 @@ +const EventBus = require('./lib/bus'); + +module.exports = EventBus; diff --git a/packages/jsdoc-bus/lib/bus.js b/packages/jsdoc-bus/lib/bus.js new file mode 100644 index 00000000..56a02398 --- /dev/null +++ b/packages/jsdoc-bus/lib/bus.js @@ -0,0 +1,50 @@ +const EventEmitter = require('events').EventEmitter; + +const cache = {}; +const hasOwnProp = Object.prototype.hasOwnProperty; + +/** + * An event bus that works the same way as a standard Node.js event emitter, with a few key + * differences: + * + * + When you create an event bus, you must specify its name. Consider using your package's name. + * + Event buses are cached and shared by default. If module A and module B both create an event bus + * called `foo`, both modules get the same event bus. This behavior makes it easier to share one + * event bus among all of the modules in your package. + * + * To prevent a new event bus from being cached and shared, set the `opts.ignoreCache` property + * to `true` when you create the event bus. (Setting this property to `true` also forces a new + * event bus to be created, even if there's a cached event bus with the same name.) + * + * @alias module:@jsdoc/bus + * @extends module:events.EventEmitter + */ +class EventBus extends EventEmitter { + /** + * Create a new event bus, or retrieve the cached event bus for the ID you specify. + * + * @param {(string|Symbol)} id - The ID for the event bus. + * @param {Object} opts - Options for the event bus. + * @param {boolean} [opts.ignoreCache=false] - Set to `true` to prevent the event bus from being + * cached, and to return a new event bus even if there is already an event bus with the same ID. + */ + constructor(id, opts = {}) { + super(); + + if (!id || (typeof id !== 'string' && typeof id !== 'symbol')) { + throw new TypeError('The `id` parameter must be a non-empty string or a symbol.'); + } + + if (hasOwnProp.call(cache, id) && !opts.ignoreCache) { + return cache[id]; + } + + this._id = id; + + if (!opts.ignoreCache) { + cache[id] = this; + } + } +} + +module.exports = EventBus; diff --git a/packages/jsdoc-bus/package.json b/packages/jsdoc-bus/package.json new file mode 100644 index 00000000..ce9edd1f --- /dev/null +++ b/packages/jsdoc-bus/package.json @@ -0,0 +1,22 @@ +{ + "name": "@jsdoc/bus", + "version": "1.0.0", + "description": "An event bus with no dependencies.", + "main": "index.js", + "repository": { + "type": "git", + "url": "https://github.com/jsdoc3/jsdoc" + }, + "keywords": [ + "jsdoc" + ], + "author": { + "name": "Jeff Williams", + "email": "jeffrey.l.williams@gmail.com" + }, + "license": "Apache-2.0", + "bugs": { + "url": "https://github.com/jsdoc3/jsdoc/issues" + }, + "homepage": "https://github.com/jsdoc3/jsdoc#readme" + } diff --git a/packages/jsdoc-bus/test/specs/index.js b/packages/jsdoc-bus/test/specs/index.js new file mode 100644 index 00000000..d84285ff --- /dev/null +++ b/packages/jsdoc-bus/test/specs/index.js @@ -0,0 +1,12 @@ +describe('@jsdoc/bus', () => { + const EventBus = require('../..'); + const LibBus = require('../../lib/bus'); + + it('exists', () => { + expect(EventBus).toBeFunction(); + }); + + it('is ./lib/bus', () => { + expect(EventBus).toBe(LibBus); + }); +}); diff --git a/packages/jsdoc-bus/test/specs/lib/bus.js b/packages/jsdoc-bus/test/specs/lib/bus.js new file mode 100644 index 00000000..b952e032 --- /dev/null +++ b/packages/jsdoc-bus/test/specs/lib/bus.js @@ -0,0 +1,66 @@ +describe('@jsdoc/bus/lib/bus', () => { + const EventBus = require('../../../lib/bus'); + const EventEmitter = require('events').EventEmitter; + + const ignoreCache = { ignoreCache: true }; + + it('inherits from EventEmitter', () => { + expect(new EventBus('foo', ignoreCache) instanceof EventEmitter).toBeTrue(); + }); + + it('accepts a string for the ID', () => { + function makeBus() { + return new EventBus('foo', ignoreCache); + } + + expect(makeBus).not.toThrow(); + }); + + it('accepts a Symbol for the ID', () => { + function makeBus() { + return new EventBus(Symbol('foo'), ignoreCache); + } + + expect(makeBus).not.toThrow(); + }); + + it('throws on bad IDs', () => { + function crashBus() { + return new EventBus(true, ignoreCache); + } + + expect(crashBus).toThrow(); + }); + + it('uses a cache by default', () => { + let fired = false; + const id = Symbol('cache-test'); + const bus1 = new EventBus(id); + const bus2 = new EventBus(id); + + bus1.once('foo', () => { + fired = true; + }); + + bus2.emit('foo'); + + expect(bus1).toBe(bus2); + expect(fired).toBeTrue(); + }); + + it('ignores the cache when asked', () => { + let fired = false; + const id = Symbol('cache-test'); + const bus1 = new EventBus(id, ignoreCache); + const bus2 = new EventBus(id, ignoreCache); + + bus1.once('foo', () => { + fired = true; + }); + + bus2.emit('foo'); + + expect(bus1).not.toBe(bus2); + expect(fired).toBeFalse(); + }); +});