First commit

.gitignore

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+dist
+node_modules

LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2023 Tao Hu
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# serq - execute functions serially
+
+This project is inspired by [seq-queue](https://github.com/changchang/seq-queue).
+
+## USAGE
+
+### BASICS
+
+```js
+let queue = new Serq()
+
+queue.push(async () => {
+  await new Promise(r => { setTimeout(r, 100) })
+  console.log('func 0')
+})
+
+queue.push(() => {
+  console.log('func 1')
+})
+
+// output:
+//
+// func 0
+// func 1
+```
+
+#### Return values
+
+```js
+let queue = new Serq()
+let ret = queue.push(() => {
+  return 'value'
+})
+
+console.log(await ret)
+
+// output:
+//
+// value
+```
+
+#### Errors
+
+```js
+let queue = new Serq()
+queue.push(() => {
+  throw new Error('an error')
+})
+.catch(err) {
+  console.log('error: ', err.message)
+}
+
+// output:
+//
+// an error
+```
+
+#### Timeouts
+
+When timeout happens, Serq executes the function next in queue.
+
+```js
+let queue = new Serq(500) // default timeout is 3000
+
+queue.push(async () => {
+  await new Promise(r => { setTimeout(r, 1000) })
+  console.log('task 0 done')
+}, {
+  ontimeout: () => {
+    console.log('timeout')
+}
+})
+
+queue.push(() => {
+  console.log('task 1 done')
+})
+
+// output:
+//
+// timeout
+// task 1 done
+// task 0 done
+```
+
+## LICENSE
+
+MIT

karma.conf.js

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+// Karma configuration
+// Generated on Thu Apr 13 2023 15:07:58 GMT+0800 (China Standard Time)
+
+const webpackConfig = require('./webpack.config.js');
+
+module.exports = function(config) {
+	config.set({
+		// base path that will be used to resolve all patterns (eg. files, exclude)
+		basePath: '',
+
+		// frameworks to use
+		// available frameworks: https://www.npmjs.com/search?q=keywords:karma-adapter
+		frameworks: ['mocha'],
+
+		plugins: [
+			require('karma-webpack'),
+			require('karma-mocha'),
+			require('karma-mocha-reporter'),
+			require('karma-chrome-launcher'),
+			require('karma-firefox-launcher'),
+			require('karma-safari-launcher'),
+			require('mochapack'),
+		],
+
+		// list of files / patterns to load in the browser
+		files: [
+			{ pattern: 'src/**/*.js', watched: true, included: false, served: false },
+			{ pattern: 'tests/**/*.js', watched: false },
+		],
+
+		// list of files / patterns to exclude
+		exclude: [],
+
+		// preprocess matching files before serving them to the browser
+		// available preprocessors: https://www.npmjs.com/search?q=keywords:karma-preprocessor
+		preprocessors: {
+			'tests/**/*.js': ['webpack'],
+		},
+
+		webpack: webpackConfig,
+
+		// test results reporter to use
+		// possible values: 'dots', 'progress'
+		// available reporters: https://www.npmjs.com/search?q=keywords:karma-reporter
+		reporters: ['mocha'],
+
+		// web server port
+		port: 9876,
+
+		// enable / disable colors in the output (reporters and logs)
+		colors: true,
+
+		// level of logging
+		// possible values: config.LOG_DISABLE || config.LOG_ERROR || config.LOG_WARN || config.LOG_INFO || config.LOG_DEBUG
+		logLevel: config.LOG_INFO,
+
+		// enable / disable watching file and executing tests whenever any file changes
+		autoWatch: true,
+
+		// start these browsers
+		// available browser launchers: https://www.npmjs.com/search?q=keywords:karma-launcher
+		browsers: ['ChromiumHeadless', 'Safari', 'FirefoxHeadless'],
+
+		// Continuous Integration mode
+		// if true, Karma captures browsers, runs the tests and exits
+		singleRun: false,
+
+		// Concurrency level
+		// how many browser instances should be started simultaneously
+		concurrency: Infinity
+	})
+}

package.json

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+{
+	"name": "serq",
+	"version": "0.1.0",
+	"description": "Serial queue.",
+	"keywords": [
+		"queue",
+		"serial"
+	],
+	"author": "Tao Hu <[email protected]>",
+	"main": "src/index.js",
+	"devDependencies": {
+		"chai": "^4.3.10",
+		"karma": "^6.4.2",
+		"karma-chrome-launcher": "^3.2.0",
+		"karma-firefox-launcher": "~2.1.2",
+		"karma-mocha": "^2.0.1",
+		"karma-mocha-reporter": "^2.2.5",
+		"karma-safari-launcher": "~1.0.0",
+		"karma-webpack": "^5.0.0",
+		"mocha": "^10.2.0",
+		"mochapack": "^2.1.4",
+		"webpack": "^5.88.2",
+		"webpack-cli": "^5.1.4"
+	},
+	"dependencies": {
+		"promise-deferred": "^2.0.4"
+	},
+	"scripts": {
+		"build": "NODE_ENV=production webpack --progress",
+		"test": "karma start karma.conf.js"
+	},
+	"license": "MIT"
+}

src/index.js

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+// Copyright (c) 2023 Tao Hu.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+'use strict';
+
+import Deferred from 'promise-deferred';
+
+let DEFAULT_TIMEOUT = 3000;
+
+class Serq {
+	static STATUS_IDLE = 0
+	static STATUS_BUSY = 1
+	static STATUS_CLOSED = 2
+
+	constructor(timeout = DEFAULT_TIMEOUT) {
+		this.id = 0
+		this.timeout = timeout
+		this.status = Serq.STATUS_IDLE;
+		this.queue = [];
+		this.pp = Promise.resolve()
+	}
+
+	push(fn, options) {
+		if (this.status !== Serq.STATUS_IDLE && this.status !== Serq.STATUS_BUSY) {
+			throw new Error(`push(): Invalid status: ${this.status}.`);
+		}
+
+		if (typeof fn !== 'function') {
+			throw new Error('fn should be a function.');
+		}
+
+		let defer = Deferred()
+		let ondone = ret => { defer.resolve(ret) }
+		let onerror = error => { defer.reject(error) }
+
+		this.queue.push({ fn: fn, ondone: ondone, onerror: onerror, ontimeout: options ? options.ontimeout : undefined });
+
+		if (this.status === Serq.STATUS_IDLE) {
+			this.status = Serq.STATUS_BUSY;
+			let self = this;
+			this.pp = this.pp.then(function() { self._next(self.id); })
+		}
+
+		return defer.promise;
+	}
+
+	close() {
+		if (this.status !== Serq.STATUS_IDLE && this.status !== Serq.STATUS_BUSY) {
+			return;
+		}
+
+		this.status = Serq.STATUS_CLOSED;
+	}
+
+	_next(id) {
+		if (this.id !== id) {
+			return
+		}
+		if (this.status !== Serq.STATUS_BUSY && this.status !== Serq.STATUS_CLOSED) {
+			return
+		}
+
+		if (this.timer) {
+			clearTimeout(this.timer);
+			this.timer = undefined;
+		}
+
+		let task = this.queue.shift();
+		if (!task) {
+			if (this.status === Serq.STATUS_BUSY) {
+				this.status = Serq.STATUS_IDLE;
+			}
+			return;
+		}
+
+		let self = this;
+		task.id = ++this.id
+
+		this.timer = setTimeout(function() {
+			self.pp = Promise.resolve().then(() => { self._next(task.id); })
+			typeof (task.ontimeout) === 'function' && task.ontimeout()
+		}, this.timeout);
+
+		this.pp = this.pp
+			.then(task.fn)
+			.catch(error => {
+				typeof task.onerror === 'function' && Promise.resolve().then(() => { task.onerror(error) })
+			})
+			.then(ret => { typeof task.ondone === 'function' && Promise.resolve().then(() => { task.ondone(ret) }) })
+			.then(() => { self._next(task.id); })
+	}
+}
+
+export default Serq