The property 'nometape' cannot be assigned to an undefined value

Question

The property 'nometape' cannot be assigned to an undefined value

Currently, I'm encountering an issue in my Angular 7 code where it states "cannot set property 'nometape' of undefined." The problem lies within the initialization process of my interface "Process" which contains an array of objects called "Etape." Here are the interfaces:

export interface Process {
    id : string,
    etapes : Etape[],
} 
export interface Etape {
    nomEtape : string,
    ordre : number,
    etat : number,
    remarque : string,
    duree: string;
    dateRDV : Date,
}

The object declaration looks like this:

  proEdit : Process = {
  id: "",
  etapes : [] 
}

To initialize the process etapes array, I use the constructor with the following:

this.proEdit.etapes = [{
         nomEtape : " ",
         ordre : 0,
         etat : 0,
         remarque : "",
         duree: "",
         dateRDV : new Date(),
       }] ;

The problem arises when I loop through the etapes array, resulting in the error message "cannot set property 'nometape' of undefined."

editProcess(){
   for(let i = 0; i < this.productForm.value.etapes.length; i++) {
     this.proEdit.etapes[i].nomEtape = this.productForm.value.etapes[i]["step"];
   }

angular typescript

Answer 1

Answer №1

It seems like the issue may not be caused by the initialization process, as you mentioned. My guess is that the problem lies in the fact that the array at index i is undefined. Have you added a new Etape object to this.proEdit.etapes?

Instead of simply setting the value at index i, have you considered trying something like this? While I cannot guarantee it will work, the concept is to add a new element to the array rather than replacing an existing one.

const newEtape: Etape = {
  nomEtape : this.productForm.value.etapes[i]["step"],
  ordre : 0,
  etat : 0,
  remarque : "",
  duree: "",
  dateRDV : new Date(),
};

this.proEdit.etapes.push(newEtape);

Answer 2

It seems like the issue may not be caused by the initialization process, as you mentioned. My guess is that the problem lies in the fact that the array at index i is undefined. Have you added a new Etape object to this.proEdit.etapes?

Instead of simply setting the value at index i, have you considered trying something like this? While I cannot guarantee it will work, the concept is to add a new element to the array rather than replacing an existing one.

const newEtape: Etape = {
  nomEtape : this.productForm.value.etapes[i]["step"],
  ordre : 0,
  etat : 0,
  remarque : "",
  duree: "",
  dateRDV : new Date(),
};

this.proEdit.etapes.push(newEtape);

Answer 3

Answer №2

The initialization code for this.proEdit.etapes currently only places a single element in the array. This may result in an error if this.productForm.value.etapes contains more than one element.

A better approach would be to create a method within the proEdit object that can synchronize an array of step values with its internal etapes array.

You can consider implementing something like the following code snippet (assuming you have lodash zip or a similar alternative):

const makeNewEtape = (step: string, etape: Etape | Object = {}): Etape => ({
  // Default values
  ordre : 0,
  etat : 0,
  remarque : "",
  duree: "",
  dateRDV : new Date(),

  // Override defaults with existing Etape values
  ...etape,

  // Override any existing nomEtape value
  nomEtape : step,

});

class ProSteps {
    private etapes: Etape[] = [ makeNewEtape(" ") ];

    syncEtapes(steps: string[]) {
      this.etapes = zip(this.etapes, steps)
        .filter(([ , step]:[ Etape,string]) => !!step)
        .map(([etape, step]:[Etape, string] ) => makeNewEtape(step, etape));
    }

    getEtapes() { // Ensure no direct access to the array
      return [...this.etapes]
    }
}

const ps = new ProSteps();
ps.syncEtapes([ 'foo', 'bar', 'baz']);

Feel free to explore and experiment with this code on the provided StackBlitz.

Answer 4

The initialization code for this.proEdit.etapes currently only places a single element in the array. This may result in an error if this.productForm.value.etapes contains more than one element.

A better approach would be to create a method within the proEdit object that can synchronize an array of step values with its internal etapes array.

You can consider implementing something like the following code snippet (assuming you have lodash zip or a similar alternative):

const makeNewEtape = (step: string, etape: Etape | Object = {}): Etape => ({
  // Default values
  ordre : 0,
  etat : 0,
  remarque : "",
  duree: "",
  dateRDV : new Date(),

  // Override defaults with existing Etape values
  ...etape,

  // Override any existing nomEtape value
  nomEtape : step,

});

class ProSteps {
    private etapes: Etape[] = [ makeNewEtape(" ") ];

    syncEtapes(steps: string[]) {
      this.etapes = zip(this.etapes, steps)
        .filter(([ , step]:[ Etape,string]) => !!step)
        .map(([etape, step]:[Etape, string] ) => makeNewEtape(step, etape));
    }

    getEtapes() { // Ensure no direct access to the array
      return [...this.etapes]
    }
}

const ps = new ProSteps();
ps.syncEtapes([ 'foo', 'bar', 'baz']);

Feel free to explore and experiment with this code on the provided StackBlitz.

The property 'nometape' cannot be assigned to an undefined value

Answer №1

Answer №2

Similar questions

Switching from callback to function in TypeScript

How can I extract fields from a response using Axios?

Determine whether one class is a parent class of another class

How can I inform Typescript that a function will never return null in this specific scenario?

Value attribute property binding

Can a function cast an object automatically if it meets certain conditions?

Can an attribute be assigned to an Angular host element without specifying a value?

Leveraging an intersection type that encompasses a portion of the union

Angular 8 is encountering an issue with an undefined global variable, specifically the variable "this

A guide to effectively unit testing StripeJs within the Karma testing framework for Angular 8

Managing various control forms to be processed individually within Angular's Reactive Forms system (Clean Code)

Whenever the condition is met, it will always be executed

Choose a specific child element to be repeated within an ngFor loop in the parent component

Transforming JavaScript into TypeScript - school project

Guide to encapsulating an angular material form within a component and making it accessible to the FormGroup as a formControl property

Repeating promises resolutions yields stagnant outcomes

Access route information external to the router outlet

What is the process for accessing product information on a separate page?

What are the steps to setting up SystemJS with Auth0?

Encountering Syntax Errors during Angular 6 production build