When using the `.push` method, the array becomes null

Question

When using the `.push` method, the array becomes null

Currently, I am in the process of developing an angular application. Within my component's .ts file, there exists an array structured as follows:

public myArray = [];
public dataFromAPI  = [];

In a particular method within this component, whenever I attempt to add an element to the said array, I encountered the following error message:

this.appService.getData.subscribe(resp => {
if (resp != null) {
    this.dataFromAPI = resp;
    this.dataFromAPI.forEach(element => {
        this.myArray.push(element)
    })
}

RROR TypeError: Cannot read properties of null (reading 'push')

No obvious mistakes are apparent in the code I've written. Normally, initializing a new array in this manner does not lead to any errors. How can I go about resolving this issue?

javascript angular typescript angular9

Answer 1

Answer №1

To properly declare variables, use the following syntax:

public myArray:any = [];
public dataFromAPI:any  = [];

When looping through the API response, access the array directly using keys within the response object:

   this.appService.getData.subscribe(resp => {
      if (resp != null) {
          resp.data.forEach(element => {
            this.myArray.push(element)
          });
      this.dataFromAPI = resp;
      }
   }

Answer 2

To properly declare variables, use the following syntax:

public myArray:any = [];
public dataFromAPI:any  = [];

When looping through the API response, access the array directly using keys within the response object:

   this.appService.getData.subscribe(resp => {
      if (resp != null) {
          resp.data.forEach(element => {
            this.myArray.push(element)
          });
      this.dataFromAPI = resp;
      }
   }

Answer 3

Answer №2

I'm unsure of the syntax for declaring an array like public myArray = [];. However, below is a working example for TypeScript.

const myArray: string[] = [];
myArray.push('string');

const myArray: number[] = [];
myArray.push(123);

const myArray: Record<string, unknown>[] = [];
myArray.push({key: 'value'});

Answer 4

I'm unsure of the syntax for declaring an array like public myArray = [];. However, below is a working example for TypeScript.

const myArray: string[] = [];
myArray.push('string');

const myArray: number[] = [];
myArray.push(123);

const myArray: Record<string, unknown>[] = [];
myArray.push({key: 'value'});

When using the `.push` method, the array becomes null

Answer №1

Answer №2

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