CODEWITHSUNDEEP
javascriptooptypescript
carella
carella

Reputation: 81

TypeScript error Cannot read property 'REPOSITORY' of undefined

New to TypeScript (but not to OO Design) I don't understand what happens

file application.ts

class
    APPLICATION{

        constructor(){
            console.log("constructor APPLICATION")
            this.database = new REPOSITORY
        }

        database: REPOSITORY
}

new APPLICATION

import { REPOSITORY } from "./repository"

file repository.ts

export

class
    REPOSITORY {

        constructor() {
            console.log("constructor de REPOSITORY")
        }

}

ANd I get the error

    this.database = new repository_1.REPOSITORY;
                                    ^

TypeError: Cannot read property 'REPOSITORY' of undefined at new APPLICATION (Z:\Documents\Phi\Developpement\TypeScript\test\application.js:6:41)

Any Idea ?

Upvotes: 4

Views: 1773

Answers (3)

carella
carella

Reputation: 81

You are perfectly right ! I thought that the compiler was in two-passes and that the order of these statements were not imposed. As I think that this import/export mecanism should be automatic, I would prefer to hide it at the end of the code ! Too bad !

Thank you

Upvotes: 2

hackerrdave
hackerrdave

Reputation: 6706

Your import statement for REPOSITORY occurs after REPOSITORY is used in the constructor for APPLICATION, which means that it is not yet defined in the constructor (the variable assignment resulting from the import statement is not hoisted). You will need to import prior to use:

import { REPOSITORY } from "./repository"

class APPLICATION {
    constructor(){
        console.log("constructor APPLICATION")
        this.database = new REPOSITORY();
    }
    database: REPOSITORY
}

Upvotes: 1

Nick
Nick

Reputation: 16586

I don't believe imports are hoisted. Try moving import { REPOSITORY } from "./repository" up in your code.

Upvotes: 0

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