                        课程
                    
                        /前端开发
                        
                            /Node.js
                        
                        /node.js调试入门

安装express 后输入node app.js 后报错“Error: Cannot find module 'expresss'”是怎么回事？

PS G:\前端\node-debug> node app.js
internal/modules/cjs/loader.js:584
    throw err;
    ^

Error: Cannot find module 'expresss'
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:582:15)
    at Function.Module._load (internal/modules/cjs/loader.js:508:25)
    at Module.require (internal/modules/cjs/loader.js:637:17)
    at require (internal/modules/cjs/helpers.js:22:18)
    at Object.<anonymous> (G:\前端\node-debug\app.js:1:81)
    at Module._compile (internal/modules/cjs/loader.js:701:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
    at Module.load (internal/modules/cjs/loader.js:600:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
    at Function.Module._load (internal/modules/cjs/loader.js:531:3)