What is the best way to store the outcome of a promise in a variable within a TypeScript constructor?

Question

What is the best way to store the outcome of a promise in a variable within a TypeScript constructor?

Is it possible to store the result of a promise in a variable within the constructor using Typescript?

I'm working with AdonisJS to retrieve data from the database, but the process involves using promises. How do I assign the result to a variable?

The variable needs to be accessible within the constructor.

Below is the code:


private teste1: any
private teste2: any

constructor(protected ctx: HttpContextContract) {

   Database.from('estoquepas').then(res => {
     this.teste1 = res;
     console.log(res)
   })

   Estoquepas.findBy('siagreId', this.IDSiagre.siagreId).then(res => {
      this.teste2 = res;
      console.log(res)
   })
   
   console.log(this.teste1)
   console.log(this.teste2)
}

Even though the console displays the values, the variables `teste1` and `teste2` remain undefined. Any assistance on resolving this issue would be greatly appreciated. Thank you for your help in advance.

javascript typescript adonis.js

Answer 1

Answer №1

In order to achieve this, you can implement a static asynchronous method in your class along with a basic constructor that only assigns values provided to it (once the async function has completed its tasks):

class Something {
    constructor (
        protected ctx: HttpContextContract,
        private teste1: any,
        private teste2: any
    ) { }

    static async create (ctx: HttpContextContract) {
        const [ teste1, teste2 ] = await Promise.all[ Database.from('estoquepas'), Estoquepas.findBy('siagreId', IDSiagre.siagreId) ]

        return new this(ctx, teste1, teste2)
    }
}

Answer 2

In order to achieve this, you can implement a static asynchronous method in your class along with a basic constructor that only assigns values provided to it (once the async function has completed its tasks):

class Something {
    constructor (
        protected ctx: HttpContextContract,
        private teste1: any,
        private teste2: any
    ) { }

    static async create (ctx: HttpContextContract) {
        const [ teste1, teste2 ] = await Promise.all[ Database.from('estoquepas'), Estoquepas.findBy('siagreId', IDSiagre.siagreId) ]

        return new this(ctx, teste1, teste2)
    }
}

What is the best way to store the outcome of a promise in a variable within a TypeScript constructor?

Answer №1

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