In the vue project, after import introduces the same file twice, the second time will be undefined

index.js
import a from"@ / views/apidocument/test/a"
console.info (a); / / has value

a.js
import c from". / c"
console.info ("bbbbbbbb",c); / / valuable
const a = {

created(){
    /* let cc = new c();
    cc.name="aaa"
    console.info(cc.name); */
    // c.name = "aaa"
}

}
export default a

c.js
import a from". / a"
console.info ("cccccccccc", a); / / undefined Why undefined?
const c = {

name: "ccc"

}
export default function () {

return {...c}

}

Javascript
Nov.15,2021

your circular dependency of the es6 module causes
when the c module executes to console.info ('cccccccccc', a) ), the a variable in the a module has not yet been assigned, so the output is undefined
you can set a delay to try, it should have a value

es6 module mechanism can be found in
in-depth understanding of ES6 module mechanism
cyclic loading of JavaScript module

Previous: How to install gitbook? offline

Next: How to cancel automatic reconnection when node-mssql uses connection pooling connection timeout

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
© 2021 CodesHelper
Advertising Contact us About us
Menu