每天一个npm包：validate-npm-package-name

function checkAppName(appName) {  const validationResult = validateProjectName(appName); // 根据validForNewPackages字段判断是否是合法的包名  if (!validationResult.validForNewPackages) {    console.error(      chalk.red(        `Cannot create a project named ${chalk.green(          `"${appName}"`        )} because of npm naming restrictions:\n`      )    );    // 打印错误、警告    [      ...(validationResult.errors || []),      ...(validationResult.warnings || []),    ].forEach(error => {      console.error(chalk.red(`  * ${error}`));    });    console.error(chalk.red('\nPlease choose a different project name.'));    // 退出进程    process.exit(1);  }  ...}

'use strict'
var semver = require('semver')
module.exports = function (version) {  // 获取node版本  version = version || process.version
  var coreModules = [    'assert',    'buffer',    'child_process',    'cluster',    'console',    'constants',    'crypto',    'dgram',    'dns',    'domain',    'events',    'fs',    'http',    'https',    'module',    'net',    'os',    'path',    'punycode',    'querystring',    'readline',    'repl',    'stream',    'string_decoder',    'sys',    'timers',    'tls',    'tty',    'url',    'util',    'vm',    'zlib'  ]
  if (semver.lt(version, '6.0.0')) coreModules.push('freelist')  if (semver.gte(version, '1.0.0')) coreModules.push('v8')  if (semver.gte(version, '1.1.0')) coreModules.push('process')  if (semver.gte(version, '8.1.0')) coreModules.push('async_hooks')  if (semver.gte(version, '8.4.0')) coreModules.push('http2')  if (semver.gte(version, '8.5.0')) coreModules.push('perf_hooks')
  return coreModules}

'use strict'
var scopedPackagePattern = new RegExp('^(?:@([^/]+?)[/])?([^/]+?)$')// 这个包是包括node内置 module的列表var builtins = require('builtins')// 保留名(黑名单)var blacklist = [  'node_modules',  'favicon.ico']
var validate = module.exports = function (name) {  // 警告：用于表示过去package name允许、如今不允许的兼容error  var warnings = []  // 存储不符号合格的包名的规则  var errors = []
  // 校验格式  if (name === null) {    errors.push('name cannot be null')    return done(warnings, errors)  }
  if (name === undefined) {    errors.push('name cannot be undefined')    return done(warnings, errors)  }
  if (typeof name !== 'string') {    errors.push('name must be a string')    return done(warnings, errors)  }
  // 校验包名长度必须大于0  if (!name.length) {    errors.push('name length must be greater than zero')  }
  // 校验包名不能以.开头  if (name.match(/^\./)) {    errors.push('name cannot start with a period')  }
  // 校验包名不能以_开头、这里复习了下match用法  // '.'.match(/^_/) === null  if (name.match(/^_/)) {    errors.push('name cannot start with an underscore')  }
  // 校验包名不能包含任何的前导、后导空格  if (name.trim() !== name) {    errors.push('name cannot contain leading or trailing spaces')  }
  // 校验包名不能为保留字  blacklist.forEach(function (blacklistedName) {    if (name.toLowerCase() === blacklistedName) {      errors.push(blacklistedName + ' is a blacklisted name')    }  })
  // Generate warnings for stuff that used to be allowed
  // core module names like http, events, util, etc  // 校验包名是否是node 内置module名、给予警告  builtins.forEach(function (builtin) {    if (name.toLowerCase() === builtin) {      warnings.push(builtin + ' is a core module name')    }  })
  // really-long-package-names-------------------------------such--length-----many---wow  // the thisisareallyreallylongpackagenameitshouldpublishdowenowhavealimittothelengthofpackagenames-poch.  // 校验包名最大长度  if (name.length > 214) {    warnings.push('name can no longer contain more than 214 characters')  }
  // mIxeD CaSe nAMEs  // 包名必须小写  if (name.toLowerCase() !== name) {    warnings.push('name can no longer contain capital letters')  }
  // 校验包名不能包含特殊字段 ~'!()*  // name.split('/').slice(-1)[0] => 获取包名、之所以要这样处理是因为  // name.split('/') 处理 npm package scope场景  // slice(-1)[0] 保证永远截取包名正确  // 'koa'.split('/').slice(-1)[0] // 'koa'  // '@babel/core'.split('/').slice(-1)[0] // 'core'  // /[~'!()*]/.test('@babel/core'.split('/').slice(-1)) // false  // /[~'!()*]/.test('@babel/co*re'.split('/').slice(-1)) // true  if (/[~'!()*]/.test(name.split('/').slice(-1)[0])) {    warnings.push('name can no longer contain special characters ("~\'!()*")')  }
  // 包名不能包含non-url-safe字符  // 关于encodeURIComponent不转义哪些字符  // https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/encodeURIComponent  if (encodeURIComponent(name) !== name) {    // 这里主要处理 scope package name 比如 @babel/core    var nameMatch = name.match(scopedPackagePattern)    if (nameMatch) {      var user = nameMatch[1] // 比如 bebel      var pkg = nameMatch[2] // 比如得到 core      // 如果没有异常 直接返回      if (encodeURIComponent(user) === user && encodeURIComponent(pkg) === pkg) {        return done(warnings, errors)      }    }
    errors.push('name can only contain URL-friendly characters')  }
  return done(warnings, errors)}
validate.scopedPackagePattern = scopedPackagePattern
// 返回结果的util方法var done = function (warnings, errors) {  var result = {    // 我们一般用该属性来判断一个包名是否合法    validForNewPackages: errors.length === 0 && warnings.length === 0,    // 这个属性是用于兼容最开始node package name带来的遗留问题，那个时候有些包名不规范    validForOldPackages: errors.length === 0,    warnings: warnings,    errors: errors  }  if (!result.warnings.length) delete result.warnings  if (!result.errors.length) delete result.errors  return result}