Typescript import/export

Question

After running app.ts, I was expecting to get this result :

{ val: 'A' } //C
{ val: 'CONSTANT'} //B

but, I'm getting this result:

{ val: 'A' } //C
{ val: undefined } //B supposed to be 'CONSTANT' ??

Any ideas?? thank you !

This is the complete code:

tsconfig.json

"target": "es6",                                     
"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"module": "commonjs",
"rootDir": "./src",
"outDir": "./dist", 
"esModuleInterop": true,
"forceConsistentCasingInFileNames": true,
"strict": true,    
"strictPropertyInitialization": false,
"skipLibCheck": true

app.ts

import { C } from "./second";
import { B } from "./first";

console.log(C)
console.log(B)

/**
 *  C depends on A
 *  B depends on CONSTANT
 **/

first.ts

import { CONSTANT } from "./second"
const A ={
    val: 'A'
}
const B = {
    val: CONSTANT
}
export { A, B }

second.ts

import { A } from "./first";
const CONSTANT = 'CONSTANT'
const C = {
    val: A.val
}
export { CONSTANT, C }

Kiritushka · Accepted Answer · 2022-06-20 21:15:52Z

2

Here is a cyclic dependency. const CONSTANT = 'CONSTANT' should be placed in a separate file

answered Jun 20, 2022 at 21:15

Kiritushka

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4 Comments

TheMlouden Over a year ago

Thank you for your answer. but I dont understand why it's considered as cyclic dependency while const C depends only on const A and const B depends only on const CONSTANT.

Kiritushka Over a year ago

The JS engine reads files line by line. 1) app.ts -> import { C } from "./second"; 2) second.ts -> import { A } from "./first"; 3) import { CONSTANT } from "./second" Here he understands that the second.ts file has already been imported earlier, so he takes it from memory, but since he has not yet read it to the end (he only counted the first line), he takes CONSTANT as undefined

TheMlouden Over a year ago

Appreciate, thank you for the clarification !

Goodies Over a year ago

It does not work for me. Simplified the case, stackoverflow.com/questions/73594930/…

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