Node.js学习6~nodejs报Error: Cannot find module ‘express‘

【现象】

D:\work\nodejs\1helloword>node helloword3.js

node:internal/modules/cjs/loader:936

  throw err;

  ^

Error: Cannot find module 'express'

Require stack:

- D:\work\nodejs\1helloword\helloword3.js

[90m    at Function.Module._resolveFilename (node:internal/modules/cjs/loader:933:15)[39m

[90m    at Function.Module._load (node:internal/modules/cjs/loader:778:27)[39m

[90m    at Module.require (node:internal/modules/cjs/loader:1005:19)[39m

[90m    at require (node:internal/modules/cjs/helpers:102:18)[39m

    at Object.<anonymous> (D:\work\nodejs\1helloword\helloword3.js:2:15)

[90m    at Module._compile (node:internal/modules/cjs/loader:1101:14)[39m

[90m    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1153:10)[39m

[90m    at Module.load (node:internal/modules/cjs/loader:981:32)[39m

[90m    at Function.Module._load (node:internal/modules/cjs/loader:822:12)[39m

[90m    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)[39m {

  code: [32m'MODULE_NOT_FOUND'[39m,

  requireStack: [ [32m'D:\\work\\nodejs\\1helloword\\helloword3.js'[39m ]

}

【解决方法】

D:\work\nodejs\1helloword>npm install express

added 50 packages in 2s