vee-cli腳手架實踐(上)
前言
隨着前端的發展，工程化已經成爲每個前端都應該重視和熟悉的方面，而做爲工程化之一的腳手架更是在平常開發中起到了十分重要的做用，而可以根據業務和項目須要爲本身的前端團隊打造個性化的屬於本身團隊的腳手架也會成爲工程師項目簡歷中的一道亮點，本文主要是借鑑vue-cli腳手架的源碼，練習本身搭建腳手架過程當中遇到的問題及本身的思考。(ps: 一款成熟的腳手架一般要包括如下功能：一、命令行；二、模板拉取；三、本地服務；四、打包構建；五、集成部署；六、周邊其餘，本文主要是對腳手架大體的功能進行必定的探究，手寫一版粗淺的腳手架，後續若是有項目實踐，會持續更新分享。)html
命令行
大框架結構
[目錄結構]前端
-
binvue
- www (全局命令執行入口鏈接，用npm link進行鏈接)
-
srcnode
- main.js (入口文件，對命令進行分發)
- create.js (建立的命令，全部建立的邏輯在此文件中書寫)
- config.js (配置的命令，全部的配置的命令在此文件中書寫)
- constants.js (常量文件，全部常量配置在此文件中)
- package.json
[目錄描述] bin下的www腳本獲取全局的執行環境，可引入入口文件，咱們在此將其導入到main.js中，全部的命令均可在main.js進行分發，爲了更好的使用，能夠將不一樣命令分到不一樣的js文件下，這裏用到了commander的包對命令進行分發，具體業務可在對應文件中進行後續擴展git
命令配置
入口
bin目錄下的可執行腳本www，github
! /usr/bin/env node
package.json中配置：面試
"bin": {
"vee-cli": "./bin/www"
},vue-cli
其可對全局下的命令進行分發，由npm link進行鏈接，若是權限不夠可能須要使用sudo等，具體的爬坑能夠參考這篇文章npm link沒有效果的問題，在入口文件中可先打印一個命令"hello vee"進行測試，如圖所示。npm
命令
完成測試後，就是命令分發的主要邏輯了，這裏主要用到了commander的包，源碼部分在下節中解讀，mapAction主要是映射命令的行爲，其中主要是alias、description、examples，而後就是每一個行爲的顯示執行了，這裏有一個關鍵代碼是require(path.resolve(__dirname,action))(...process.argv.slice(3))獲取對應的文件名來進行解析，這樣就能夠把各個功能抽離到對應文件裏去作具體的邏輯編程
const program = require('commander');
const { version } = require('./constants');
const path = require('path');
const mapAction = {
create: {
alias: 'c',
description: 'create a project',
examples: [
'vee-cli create <project-name>'
],
},
config: {
alias: 'conf',
description: 'config project variable',
examples: [
'vee-cli config set <k> <v>',
'vee-cli config get <k>',
],
},
'*': {
alias: '',
description: 'command not found',
examples: [],
}
}
//可使用Reflect，好處是能夠遍歷Symbol
Object.keys(mapAction).forEach((action) => {
program.command(action)
.alias(mapAction[action].alias)
.description(mapAction[action].description)
.action(() => {
if (action === '*') {
console.log(mapAction[action].description)
} else {
console.log(action);
require(path.resolve(__dirname,action))(...process.argv.slice(3))
}
})
});
program.on('--help',()=>{
console.log('\r\nExamples:');
Object.keys(mapAction).forEach((action)=>{
mapAction[action].examples.forEach(example=>{
console.log(' '+example)
})
})
});
program.version(version).parse(process.argv);
相關包源碼分析
commander是tj大佬寫的，包主要依賴着event、child_process、fs、path、Error五個node核心模塊，其中EventEmitter的實現更是前端面試中常見的筆試題，具體請看編程題-方法庫-實現EventEmitter，所以搭建腳手架，node是基礎！
- 依賴
const EventEmitter = require('events').EventEmitter; // 事件觸發與事件監聽器功能的封裝
const spawn = require('child_process').spawn; // 利用給定的命令以及參數執行一個新的進程
const path = require('path'); // 路徑模塊
const fs = require('fs'); // 文件模塊
- Option類
class Option {
constructor(flags, description) {
this.flags = flags;
this.required = flags.indexOf('<') >= 0;
this.optional = flags.indexOf('[') >= 0;
this.mandatory = false;
this.negate = flags.indexOf('-no-') !== -1;
const flagParts = flags.split(/[ ,|]+/);
if (flagParts.length > 1 && !/^[[<]/.test(flagParts[1])) this.short = flagParts.shift();
this.long = flagParts.shift();
this.description = description || '';
this.defaultValue = undefined;
}
name() {
return this.long.replace(/^--/, '');
};
attributeName() {
return camelcase(this.name().replace(/^no-/, ''));
};
is(arg) {
return this.short === arg || this.long === arg;
};
}
- CommandError類
class CommanderError extends Error {
constructor(exitCode, code, message) {
super(message);
// properly capture stack trace in Node.js
Error.captureStackTrace(this, this.constructor);
this.name = this.constructor.name;
this.code = code;
this.exitCode = exitCode;
this.nestedError = undefined;
}
}
- Command類
class Command extends EventEmitter {
constructor(name) {
super();
this.commands = [];
this.options = [];
this.parent = null;
this._allowUnknownOption = false;
this._args = [];
this.rawArgs = null;
this._scriptPath = null;
this._name = name || '';
this._optionValues = {};
this._storeOptionsAsProperties = true;
this._passCommandToAction = true;
this._actionResults = [];
this._actionHandler = null;
this._executableHandler = false;
this._executableFile = null;
this._defaultCommandName = null;
this._exitCallback = null;
this._aliases = [];
this._hidden = false;
this._helpFlags = '-h, --help';
this._helpDescription = 'display help for command';
this._helpShortFlag = '-h';
this._helpLongFlag = '--help';
this._hasImplicitHelpCommand = undefined;
this._helpCommandName = 'help';
this._helpCommandnameAndArgs = 'help [command]';
this._helpCommandDescription = 'display help for command';
}
command(nameAndArgs, actionOptsOrExecDesc, execOpts) {
let desc = actionOptsOrExecDesc;
let opts = execOpts;
if (typeof desc === 'object' && desc !== null) {
opts = desc;
desc = null;
}
opts = opts || {};
const args = nameAndArgs.split(/ +/);
const cmd = this.createCommand(args.shift());
if (desc) {
cmd.description(desc);
cmd._executableHandler = true;
}
if (opts.isDefault) this._defaultCommandName = cmd._name;
cmd._hidden = !!(opts.noHelp || opts.hidden);
cmd._helpFlags = this._helpFlags;
cmd._helpDescription = this._helpDescription;
cmd._helpShortFlag = this._helpShortFlag;
cmd._helpLongFlag = this._helpLongFlag;
cmd._helpCommandName = this._helpCommandName;
cmd._helpCommandnameAndArgs = this._helpCommandnameAndArgs;
cmd._helpCommandDescription = this._helpCommandDescription;
cmd._exitCallback = this._exitCallback;
cmd._storeOptionsAsProperties = this._storeOptionsAsProperties;
cmd._passCommandToAction = this._passCommandToAction;
cmd._executableFile = opts.executableFile || null;
this.commands.push(cmd);
cmd._parseExpectedArgs(args);
cmd.parent = this;
if (desc) return this;
return cmd;
};
createCommand(name) {
return new Command(name);
};
addCommand(cmd, opts) {
if (!cmd._name) throw new Error('Command passed to .addCommand() must have a name');
function checkExplicitNames(commandArray) {
commandArray.forEach((cmd) => {
if (cmd._executableHandler && !cmd._executableFile) {
throw new Error(`Must specify executableFile for deeply nested executable: ${cmd.name()}`);
}
checkExplicitNames(cmd.commands);
});
}
checkExplicitNames(cmd.commands);
opts = opts || {};
if (opts.isDefault) this._defaultCommandName = cmd._name;
if (opts.noHelp || opts.hidden) cmd._hidden = true;
this.commands.push(cmd);
cmd.parent = this;
return this;
};
arguments(desc) {
return this._parseExpectedArgs(desc.split(/ +/));
};
addHelpCommand(enableOrNameAndArgs, description) {
if (enableOrNameAndArgs === false) {
this._hasImplicitHelpCommand = false;
} else {
this._hasImplicitHelpCommand = true;
if (typeof enableOrNameAndArgs === 'string') {
this._helpCommandName = enableOrNameAndArgs.split(' ')[0];
this._helpCommandnameAndArgs = enableOrNameAndArgs;
}
this._helpCommandDescription = description || this._helpCommandDescription;
}
return this;
};
_lazyHasImplicitHelpCommand() {
if (this._hasImplicitHelpCommand === undefined) {
this._hasImplicitHelpCommand = this.commands.length && !this._actionHandler && !this._findCommand('help');
}
return this._hasImplicitHelpCommand;
};
_parseExpectedArgs(args) {
if (!args.length) return;
args.forEach((arg) => {
const argDetails = {
required: false,
name: '',
variadic: false
};
switch (arg[0]) {
case '<':
argDetails.required = true;
argDetails.name = arg.slice(1, -1);
break;
case '[':
argDetails.name = arg.slice(1, -1);
break;
}
if (argDetails.name.length > 3 && argDetails.name.slice(-3) === '...') {
argDetails.variadic = true;
argDetails.name = argDetails.name.slice(0, -3);
}
if (argDetails.name) {
this._args.push(argDetails);
}
});
this._args.forEach((arg, i) => {
if (arg.variadic && i < this._args.length - 1) {
throw new Error(`only the last argument can be variadic '${arg.name}'`);
}
});
return this;
};
exitOverride(fn) {
if (fn) {
this._exitCallback = fn;
} else {
this._exitCallback = (err) => {
if (err.code !== 'commander.executeSubCommandAsync') {
throw err;
} else {
}
};
}
return this;
};
_exit(exitCode, code, message) {
if (this._exitCallback) {
this._exitCallback(new CommanderError(exitCode, code, message));
}
process.exit(exitCode);
};
action(fn) {
const listener = (args) => {
const expectedArgsCount = this._args.length;
const actionArgs = args.slice(0, expectedArgsCount);
if (this._passCommandToAction) {
actionArgs[expectedArgsCount] = this;
} else {
actionArgs[expectedArgsCount] = this.opts();
}
if (args.length > expectedArgsCount) {
actionArgs.push(args.slice(expectedArgsCount));
}
const actionResult = fn.apply(this, actionArgs);
let rootCommand = this;
while (rootCommand.parent) {
rootCommand = rootCommand.parent;
}
rootCommand._actionResults.push(actionResult);
};
this._actionHandler = listener;
return this;
};
_optionEx(config, flags, description, fn, defaultValue) {
const option = new Option(flags, description);
const oname = option.name();
const name = option.attributeName();
option.mandatory = !!config.mandatory;
if (typeof fn !== 'function') {
if (fn instanceof RegExp) {
const regex = fn;
fn = (val, def) => {
const m = regex.exec(val);
return m ? m[0] : def;
};
} else {
defaultValue = fn;
fn = null;
}
}
if (option.negate || option.optional || option.required || typeof defaultValue === 'boolean') {
if (option.negate) {
const positiveLongFlag = option.long.replace(/^--no-/, '--');
defaultValue = this._findOption(positiveLongFlag) ? this._getOptionValue(name) : true;
}
if (defaultValue !== undefined) {
this._setOptionValue(name, defaultValue);
option.defaultValue = defaultValue;
}
}
this.options.push(option);
this.on('option:' + oname, (val) => {
if (val !== null && fn) {
val = fn(val, this._getOptionValue(name) === undefined ? defaultValue : this._getOptionValue(name));
}
if (typeof this._getOptionValue(name) === 'boolean' || typeof this._getOptionValue(name) === 'undefined') {
if (val == null) {
this._setOptionValue(name, option.negate
? false
: defaultValue || true);
} else {
this._setOptionValue(name, val);
}
} else if (val !== null) {
this._setOptionValue(name, option.negate ? false : val);
}
});
return this;
};
option(flags, description, fn, defaultValue) {
return this._optionEx({}, flags, description, fn, defaultValue);
};
requiredOption(flags, description, fn, defaultValue) {
return this._optionEx({ mandatory: true }, flags, description, fn, defaultValue);
};
allowUnknownOption(arg) {
this._allowUnknownOption = (arg === undefined) || arg;
return this;
};
storeOptionsAsProperties(value) {
this._storeOptionsAsProperties = (value === undefined) || value;
if (this.options.length) {
throw new Error('call .storeOptionsAsProperties() before adding options');
}
return this;
};
passCommandToAction(value) {
this._passCommandToAction = (value === undefined) || value;
return this;
};
_setOptionValue(key, value) {
if (this._storeOptionsAsProperties) {
this[key] = value;
} else {
this._optionValues[key] = value;
}
};
_getOptionValue(key) {
if (this._storeOptionsAsProperties) {
return this[key];
}
return this._optionValues[key];
};
parse(argv, parseOptions) {
if (argv !== undefined && !Array.isArray(argv)) {
throw new Error('first parameter to parse must be array or undefined');
}
parseOptions = parseOptions || {};
if (argv === undefined) {
argv = process.argv;
if (process.versions && process.versions.electron) {
parseOptions.from = 'electron';
}
}
this.rawArgs = argv.slice();
let userArgs;
switch (parseOptions.from) {
case undefined:
case 'node':
this._scriptPath = argv[1];
userArgs = argv.slice(2);
break;
case 'electron':
if (process.defaultApp) {
this._scriptPath = argv[1];
userArgs = argv.slice(2);
} else {
userArgs = argv.slice(1);
}
break;
case 'user':
userArgs = argv.slice(0);
break;
default:
throw new Error(`unexpected parse option { from: '${parseOptions.from}' }`);
}
if (!this._scriptPath && process.mainModule) {
this._scriptPath = process.mainModule.filename;
}
this._name = this._name || (this._scriptPath && path.basename(this._scriptPath, path.extname(this._scriptPath)));
this._parseCommand([], userArgs);
return this;
};
parseAsync(argv, parseOptions) {
this.parse(argv, parseOptions);
return Promise.all(this._actionResults).then(() => this);
};
_executeSubCommand(subcommand, args) {
args = args.slice();
let launchWithNode = false;
const sourceExt = ['.js', '.ts', '.mjs'];
this._checkForMissingMandatoryOptions();
const scriptPath = this._scriptPath;
let baseDir;
try {
const resolvedLink = fs.realpathSync(scriptPath);
baseDir = path.dirname(resolvedLink);
} catch (e) {
baseDir = '.';
}
let bin = path.basename(scriptPath, path.extname(scriptPath)) + '-' + subcommand._name;
if (subcommand._executableFile) {
bin = subcommand._executableFile;
}
const localBin = path.join(baseDir, bin);
if (fs.existsSync(localBin)) {
bin = localBin;
} else {
sourceExt.forEach((ext) => {
if (fs.existsSync(`${localBin}${ext}`)) {
bin = `${localBin}${ext}`;
}
});
}
launchWithNode = sourceExt.includes(path.extname(bin));
let proc;
if (process.platform !== 'win32') {
if (launchWithNode) {
args.unshift(bin);
args = incrementNodeInspectorPort(process.execArgv).concat(args);
proc = spawn(process.argv[0], args, { stdio: 'inherit' });
} else {
proc = spawn(bin, args, { stdio: 'inherit' });
}
} else {
args.unshift(bin);
args = incrementNodeInspectorPort(process.execArgv).concat(args);
proc = spawn(process.execPath, args, { stdio: 'inherit' });
}
const signals = ['SIGUSR1', 'SIGUSR2', 'SIGTERM', 'SIGINT', 'SIGHUP'];
signals.forEach((signal) => {
process.on(signal, () => {
if (proc.killed === false && proc.exitCode === null) {
proc.kill(signal);
}
});
});
const exitCallback = this._exitCallback;
if (!exitCallback) {
proc.on('close', process.exit.bind(process));
} else {
proc.on('close', () => {
exitCallback(new CommanderError(process.exitCode || 0, 'commander.executeSubCommandAsync', '(close)'));
});
}
proc.on('error', (err) => {
if (err.code === 'ENOENT') {
const executableMissing = `'${bin}' does not exist
- if '${subcommand._name}' is not meant to be an executable command, remove description parameter from '.command()' and use '.description()' instead
- if the default executable name is not suitable, use the executableFile option to supply a custom name`;
throw new Error(executableMissing);
} else if (err.code === 'EACCES') {
throw new Error(`'${bin}' not executable`);
}
if (!exitCallback) {
process.exit(1);
} else {
const wrappedError = new CommanderError(1, 'commander.executeSubCommandAsync', '(error)');
wrappedError.nestedError = err;
exitCallback(wrappedError);
}
});
this.runningCommand = proc;
};
_dispatchSubcommand(commandName, operands, unknown) {
const subCommand = this._findCommand(commandName);
if (!subCommand) this._helpAndError();
if (subCommand._executableHandler) {
this._executeSubCommand(subCommand, operands.concat(unknown));
} else {
subCommand._parseCommand(operands, unknown);
}
};
_parseCommand(operands, unknown) {
const parsed = this.parseOptions(unknown);
operands = operands.concat(parsed.operands);
unknown = parsed.unknown;
this.args = operands.concat(unknown);
if (operands && this._findCommand(operands[0])) {
this._dispatchSubcommand(operands[0], operands.slice(1), unknown);
} else if (this._lazyHasImplicitHelpCommand() && operands[0] === this._helpCommandName) {
if (operands.length === 1) {
this.help();
} else {
this._dispatchSubcommand(operands[1], [], [this._helpLongFlag]);
}
} else if (this._defaultCommandName) {
outputHelpIfRequested(this, unknown);
this._dispatchSubcommand(this._defaultCommandName, operands, unknown);
} else {
if (this.commands.length && this.args.length === 0 && !this._actionHandler && !this._defaultCommandName) {
this._helpAndError();
}
outputHelpIfRequested(this, parsed.unknown);
this._checkForMissingMandatoryOptions();
if (parsed.unknown.length > 0) {
this.unknownOption(parsed.unknown[0]);
}
if (this._actionHandler) {
const args = this.args.slice();
this._args.forEach((arg, i) => {
if (arg.required && args[i] == null) {
this.missingArgument(arg.name);
} else if (arg.variadic) {
args[i] = args.splice(i);
}
});
this._actionHandler(args);
this.emit('command:' + this.name(), operands, unknown);
} else if (operands.length) {
if (this._findCommand('*')) {
this._dispatchSubcommand('*', operands, unknown);
} else if (this.listenerCount('command:*')) {
this.emit('command:*', operands, unknown);
} else if (this.commands.length) {
this.unknownCommand();
}
} else if (this.commands.length) {
this._helpAndError();
} else {
}
}
};
_findCommand(name) {
if (!name) return undefined;
return this.commands.find(cmd => cmd._name === name || cmd._aliases.includes(name));
};
_findOption(arg) {
return this.options.find(option => option.is(arg));
};
_checkForMissingMandatoryOptions() {
for (let cmd = this; cmd; cmd = cmd.parent) {
cmd.options.forEach((anOption) => {
if (anOption.mandatory && (cmd._getOptionValue(anOption.attributeName()) === undefined)) {
cmd.missingMandatoryOptionValue(anOption);
}
});
}
};
parseOptions(argv) {
const operands = [];
const unknown = [];
let dest = operands;
const args = argv.slice();
function maybeOption(arg) {
return arg.length > 1 && arg[0] === '-';
}
while (args.length) {
const arg = args.shift();
if (arg === '--') {
if (dest === unknown) dest.push(arg);
dest.push(...args);
break;
}
if (maybeOption(arg)) {
const option = this._findOption(arg);
if (option) {
if (option.required) {
const value = args.shift();
if (value === undefined) this.optionMissingArgument(option);
this.emit(`option:${option.name()}`, value);
} else if (option.optional) {
let value = null;
if (args.length > 0 && !maybeOption(args[0])) {
value = args.shift();
}
this.emit(`option:${option.name()}`, value);
} else {
this.emit(`option:${option.name()}`);
}
continue;
}
}
if (arg.length > 2 && arg[0] === '-' && arg[1] !== '-') {
const option = this._findOption(`-${arg[1]}`);
if (option) {
if (option.required || option.optional) {
this.emit(`option:${option.name()}`, arg.slice(2));
} else {
this.emit(`option:${option.name()}`);
args.unshift(`-${arg.slice(2)}`);
}
continue;
}
}
if (/^--[^=]+=/.test(arg)) {
const index = arg.indexOf('=');
const option = this._findOption(arg.slice(0, index));
if (option && (option.required || option.optional)) {
this.emit(`option:${option.name()}`, arg.slice(index + 1));
continue;
}
}
if (arg.length > 1 && arg[0] === '-') {
dest = unknown;
}
dest.push(arg);
}
return { operands, unknown };
};
opts() {
if (this._storeOptionsAsProperties) {
const result = {};
const len = this.options.length;
for (let i = 0; i < len; i++) {
const key = this.options[i].attributeName();
result[key] = key === this._versionOptionName ? this._version : this[key];
}
return result;
}
return this._optionValues;
};
missingArgument(name) {
const message = `error: missing required argument '${name}'`;
console.error(message);
this._exit(1, 'commander.missingArgument', message);
};
optionMissingArgument(option, flag) {
let message;
if (flag) {
message = `error: option '${option.flags}' argument missing, got '${flag}'`;
} else {
message = `error: option '${option.flags}' argument missing`;
}
console.error(message);
this._exit(1, 'commander.optionMissingArgument', message);
};
missingMandatoryOptionValue(option) {
const message = `error: required option '${option.flags}' not specified`;
console.error(message);
this._exit(1, 'commander.missingMandatoryOptionValue', message);
};
unknownOption(flag) {
if (this._allowUnknownOption) return;
const message = `error: unknown option '${flag}'`;
console.error(message);
this._exit(1, 'commander.unknownOption', message);
};
unknownCommand() {
const partCommands = [this.name()];
for (let parentCmd = this.parent; parentCmd; parentCmd = parentCmd.parent) {
partCommands.unshift(parentCmd.name());
}
const fullCommand = partCommands.join(' ');
const message = `error: unknown command '${this.args[0]}'. See '${fullCommand} ${this._helpLongFlag}'.`;
console.error(message);
this._exit(1, 'commander.unknownCommand', message);
};
version(str, flags, description) {
if (str === undefined) return this._version;
this._version = str;
flags = flags || '-V, --version';
description = description || 'output the version number';
const versionOption = new Option(flags, description);
this._versionOptionName = versionOption.long.substr(2) || 'version';
this.options.push(versionOption);
this.on('option:' + this._versionOptionName, () => {
process.stdout.write(str + '\n');
this._exit(0, 'commander.version', str);
});
return this;
};
description(str, argsDescription) {
if (str === undefined && argsDescription === undefined) return this._description;
this._description = str;
this._argsDescription = argsDescription;
return this;
};
alias(alias) {
if (alias === undefined) return this._aliases[0];
let command = this;
if (this.commands.length !== 0 && this.commands[this.commands.length - 1]._executableHandler) {
command = this.commands[this.commands.length - 1];
}
if (alias === command._name) throw new Error('Command alias can\'t be the same as its name');
command._aliases.push(alias);
return this;
};
aliases(aliases) {
if (aliases === undefined) return this._aliases;
aliases.forEach((alias) => this.alias(alias));
return this;
};
usage(str) {
if (str === undefined) {
if (this._usage) return this._usage;
const args = this._args.map((arg) => {
return humanReadableArgName(arg);
});
return '[options]' +
(this.commands.length ? ' [command]' : '') +
(this._args.length ? ' ' + args.join(' ') : '');
}
this._usage = str;
return this;
};
name(str) {
if (str === undefined) return this._name;
this._name = str;
return this;
};
prepareCommands() {
const commandDetails = this.commands.filter((cmd) => {
return !cmd._hidden;
}).map((cmd) => {
const args = cmd._args.map((arg) => {
return humanReadableArgName(arg);
}).join(' ');
return [
cmd._name +
(cmd._aliases[0] ? '|' + cmd._aliases[0] : '') +
(cmd.options.length ? ' [options]' : '') +
(args ? ' ' + args : ''),
cmd._description
];
});
if (this._lazyHasImplicitHelpCommand()) {
commandDetails.push([this._helpCommandnameAndArgs, this._helpCommandDescription]);
}
return commandDetails;
};
largestCommandLength() {
const commands = this.prepareCommands();
return commands.reduce((max, command) => {
return Math.max(max, command[0].length);
}, 0);
};
largestOptionLength() {
const options = [].slice.call(this.options);
options.push({
flags: this._helpFlags
});
return options.reduce((max, option) => {
return Math.max(max, option.flags.length);
}, 0);
};
largestArgLength() {
return this._args.reduce((max, arg) => {
return Math.max(max, arg.name.length);
}, 0);
};
padWidth() {
let width = this.largestOptionLength();
if (this._argsDescription && this._args.length) {
if (this.largestArgLength() > width) {
width = this.largestArgLength();
}
}
if (this.commands && this.commands.length) {
if (this.largestCommandLength() > width) {
width = this.largestCommandLength();
}
}
return width;
};
optionHelp() {
const width = this.padWidth();
const columns = process.stdout.columns || 80;
const descriptionWidth = columns - width - 4;
function padOptionDetails(flags, description) {
return pad(flags, width) + ' ' + optionalWrap(description, descriptionWidth, width + 2);
};
const help = this.options.map((option) => {
const fullDesc = option.description +
((!option.negate && option.defaultValue !== undefined) ? ' (default: ' + JSON.stringify(option.defaultValue) + ')' : '');
return padOptionDetails(option.flags, fullDesc);
});
const showShortHelpFlag = this._helpShortFlag && !this._findOption(this._helpShortFlag);
const showLongHelpFlag = !this._findOption(this._helpLongFlag);
if (showShortHelpFlag || showLongHelpFlag) {
let helpFlags = this._helpFlags;
if (!showShortHelpFlag) {
helpFlags = this._helpLongFlag;
} else if (!showLongHelpFlag) {
helpFlags = this._helpShortFlag;
}
help.push(padOptionDetails(helpFlags, this._helpDescription));
}
return help.join('\n');
};
commandHelp() {
if (!this.commands.length && !this._lazyHasImplicitHelpCommand()) return '';
const commands = this.prepareCommands();
const width = this.padWidth();
const columns = process.stdout.columns || 80;
const descriptionWidth = columns - width - 4;
return [
'Commands:',
commands.map((cmd) => {
const desc = cmd[1] ? ' ' + cmd[1] : '';
return (desc ? pad(cmd[0], width) : cmd[0]) + optionalWrap(desc, descriptionWidth, width + 2);
}).join('\n').replace(/^/gm, ' '),
''
].join('\n');
};
helpInformation() {
let desc = [];
if (this._description) {
desc = [
this._description,
''
];
const argsDescription = this._argsDescription;
if (argsDescription && this._args.length) {
const width = this.padWidth();
const columns = process.stdout.columns || 80;
const descriptionWidth = columns - width - 5;
desc.push('Arguments:');
desc.push('');
this._args.forEach((arg) => {
desc.push(' ' + pad(arg.name, width) + ' ' + wrap(argsDescription[arg.name], descriptionWidth, width + 4));
});
desc.push('');
}
}
let cmdName = this._name;
if (this._aliases[0]) {
cmdName = cmdName + '|' + this._aliases[0];
}
let parentCmdNames = '';
for (let parentCmd = this.parent; parentCmd; parentCmd = parentCmd.parent) {
parentCmdNames = parentCmd.name() + ' ' + parentCmdNames;
}
const usage = [
'Usage: ' + parentCmdNames + cmdName + ' ' + this.usage(),
''
];
let cmds = [];
const commandHelp = this.commandHelp();
if (commandHelp) cmds = [commandHelp];
const options = [
'Options:',
'' + this.optionHelp().replace(/^/gm, ' '),
''
];
return usage
.concat(desc)
.concat(options)
.concat(cmds)
.join('\n');
};
outputHelp(cb) {
if (!cb) {
cb = (passthru) => {
return passthru;
};
}
const cbOutput = cb(this.helpInformation());
if (typeof cbOutput !== 'string' && !Buffer.isBuffer(cbOutput)) {
throw new Error('outputHelp callback must return a string or a Buffer');
}
process.stdout.write(cbOutput);
this.emit(this._helpLongFlag);
};
helpOption(flags, description) {
this._helpFlags = flags || this._helpFlags;
this._helpDescription = description || this._helpDescription;
const splitFlags = this._helpFlags.split(/[ ,|]+/);
this._helpShortFlag = undefined;
if (splitFlags.length > 1) this._helpShortFlag = splitFlags.shift();
this._helpLongFlag = splitFlags.shift();
return this;
};
help(cb) {
this.outputHelp(cb);
this._exit(process.exitCode || 0, 'commander.help', '(outputHelp)');
};
_helpAndError() {
this.outputHelp();
this._exit(1, 'commander.help', '(outputHelp)');
};
};
- 導出及函數方法
exports = module.exports = new Command();
exports.program = exports;
exports.Command = Command;
exports.Option = Option;
exports.CommanderError = CommanderError;
function camelcase(flag) {
return flag.split('-').reduce((str, word) => {
return str + word[0].toUpperCase() + word.slice(1);
});
}
function pad(str, width) {
const len = Math.max(0, width - str.length);
return str + Array(len + 1).join(' ');
}
function wrap(str, width, indent) {
const regex = new RegExp('.{1,' + (width - 1) + '}([\\s\u200B]|$)|[^\\s\u200B]+?([\\s\u200B]|$)', 'g');
const lines = str.match(regex) || [];
return lines.map((line, i) => {
if (line.slice(-1) === '\n') {
line = line.slice(0, line.length - 1);
}
return ((i > 0 && indent) ? Array(indent + 1).join(' ') : '') + line.trimRight();
}).join('\n');
}
function optionalWrap(str, width, indent) {
if (str.match(/[\n]\s+/)) return str;
const minWidth = 40;
if (width < minWidth) return str;
return wrap(str, width, indent);
}
function outputHelpIfRequested(cmd, args) {
const helpOption = args.find(arg => arg === cmd._helpLongFlag || arg === cmd._helpShortFlag);
if (helpOption) {
cmd.outputHelp();
cmd._exit(0, 'commander.helpDisplayed', '(outputHelp)');
}
}
function humanReadableArgName(arg) {
const nameOutput = arg.name + (arg.variadic === true ? '...' : '');
return arg.required
? '<' + nameOutput + '>'
: '[' + nameOutput + ']';
}
function incrementNodeInspectorPort(args) {
return args.map((arg) => {
let result = arg;
if (arg.indexOf('--inspect') === 0) {
let debugOption;
let debugHost = '127.0.0.1';
let debugPort = '9229';
let match;
if ((match = arg.match(/^(--inspect(-brk)?)$/)) !== null) {
debugOption = match[1];
} else if ((match = arg.match(/^(--inspect(-brk|-port)?)=([^:]+)$/)) !== null) {
debugOption = match[1];
if (/^\d+$/.test(match[3])) {
debugPort = match[3];
} else {
debugHost = match[3];
}
} else if ((match = arg.match(/^(--inspect(-brk|-port)?)=([^:]+):(\d+)$/)) !== null) {
debugOption = match[1];
debugHost = match[3];
debugPort = match[4];
}
if (debugOption && debugPort !== '0') {
result = `${debugOption}=${debugHost}:${parseInt(debugPort) + 1}`;
}
}
return result;
});
}
總結
本篇主要描述的是自主搭建腳手架的基本配置以及基本命令的配置上，具體的各類命令配置後事如何，且聽下回分解
未完待續...
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