JavaScript Arguments Object返回意外输出-Java 学习之路

我有一个函数，应该检查传递给函数的参数是否未定义，如果其中任何一个是，则返回false . 我正在使用 node.js .

我遇到的问题是将 arguments 对象记录到控制台会返回意外的输出 .

这是我的箭头功能：

var checkYargsExist = () => {
    //console.log(arguments);
    for (x in arguments) {  
        if (arguments[x] === undefined) {
            return false;
        }
    }   
}

假设：var alpha =“apple”; var beta =“banana”;

如果我这样调用函数： checkYargsExist(alpha, beta) ，我希望 console.log() 吐出 [alpha, beta] ，然后比较 "apple" === undefined ， "banana" === undefined 但是我的终端正在吐出这样的东西：

{ '0': {},
  '1': 
   { [Function: require]
     resolve: [Function: resolve],
     main: 
      Module {
        id: '.',
        exports: {},
        parent: null,
        filename: '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/app.js',
        loaded: false,
        children: [Object],
        paths: [Object] },
     extensions: { '.js': [Function], '.json': [Function], '.node': [Function] },
     cache: 
      { '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/app.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/lodash/lodash.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/yargs.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/lodash.assign/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/lib/command.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/lib/completion.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs-parser/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/camelcase/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs-parser/lib/tokenize-arg-string.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/lib/usage.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/cliui/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/string-width/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/strip-ansi/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/ansi-regex/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/code-point-at/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/is-fullwidth-code-point/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/number-is-nan/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/wrap-ansi/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/decamelize/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/window-size/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/lib/obj-filter.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/set-blocking/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/yargs/lib/validation.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/y18n/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/read-pkg-up/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/find-up/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/path-exists/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/pinkie-promise/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/read-pkg/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/load-json-file/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/graceful-fs/graceful-fs.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/graceful-fs/polyfills.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/graceful-fs/fs.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/graceful-fs/legacy-streams.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/strip-bom/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/is-utf8/is-utf8.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/parse-json/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/error-ex/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/is-arrayish/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/parse-json/vendor/parse.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/parse-json/vendor/unicode.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/pify/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/normalize.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/fixer.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/semver/semver.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/validate-npm-package-license/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/spdx-expression-parse/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/spdx-expression-parse/parser.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/spdx-correct/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/spdx-license-ids/spdx-license-ids.json': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/hosted-git-info/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/hosted-git-info/git-host-info.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/hosted-git-info/git-host.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/is-builtin-module/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/builtin-modules/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/extract_description.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/typos.json': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/make_warning.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/normalize-package-data/lib/warning_messages.json': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/path-type/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/pkg-conf/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/object-assign/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/symbol/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/require-main-filename/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/notes.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/os-locale/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/lcid/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/invert-kv/index.js': [Object],
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules/lcid/lcid.json': [Object] } },
  '2': 
   Module {
     id: '.',
     exports: {},
     parent: null,
     filename: '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/app.js',
     loaded: false,
     children: [ [Object], [Object], [Object] ],
     paths: 
      [ '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/node_modules',
        '/Users/raigovind93/Dropbox/Localhost/Coding/Node/node_modules',
        '/Users/raigovind93/Dropbox/Localhost/Coding/node_modules',
        '/Users/raigovind93/Dropbox/Localhost/node_modules',
        '/Users/raigovind93/Dropbox/node_modules',
        '/Users/raigovind93/node_modules',
        '/Users/node_modules',
        '/node_modules' ] },
  '3': '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app/app.js',
  '4': '/Users/raigovind93/Dropbox/Localhost/Coding/Node/notes-node-app' }

我究竟做错了什么？谢谢！

1 回答

4

From MDN：

与函数表达式相比，箭头函数表达式具有更短的语法，并且不绑定它自己的this，arguments，super或new.target .

您正在检查函数创建范围的 arguments .

如果要使用函数的 arguments ，则不要使用箭头功能创建它 . 坚持使用常规函数声明或函数表达式 .

回复于 2024-05-08T09:19:30+08:00

JavaScript Arguments Object返回意外输出

1 回答

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