“Cannot read property 'push' of undefined ” Angular 9 component

Question

I'm trying to create a nested array in my angular 9 component so I can call it in the template. I'm not sure whether the problem is formatting or if there is something I'm doing fundamentally wrong. I keep getting this error msg: Cannot read property 'push' of undefined

Here is my typescript:

import { Component, OnInit } from '@angular/core';

@Component({
  selector: 'ngx-analysis',
  templateUrl: './analysis.component.html',
  styleUrls: ['./analysis.component.scss']
})
export class AnalysisComponent implements OnInit {

    persuadables: [{'icon':string, 'desc':string, 'status':string}];

    constructor() { }

    ngOnInit() {
        this.persuadablePush();
    }

significance(score, name, arr){

        if (score == 1.0){
            arr.push({'icon':'checkmark-done-circle', 'desc': 'Very ' + name.toLowerCase(), 'status':'success'}) ;
        }
        else if (score == 0.5){
            arr.push({'icon':'checkmark-circle', 'desc':name, 'status':'info'}) ;
 
        }
        else if (score == 0.0){
            arr.push({'icon':'close-circle', 'desc': 'Not ' + name.toLowerCase(), 'status':'danger'}) ;

        }
    }
persuadablePush(){

        for( let i=5; i<10; i++ ){

            this.significance(
                this.insights['consumption_preferences'][0]['consumption_preferences'][i]['score'],// =number
                this.insights['consumption_preferences'][0]['consumption_preferences'][i]['name'],// =string
                this.persuadables
            )
        }
    }

and here's my HTML:

<nb-card size="small">
      <nb-card-header>Persuadables</nb-card-header>
      <nb-card-body>
        <nb-list *ngFor='let obj of persuadables'>
            <nb-icon icon='obj.icon' status='obj.status'></nb-icon>
            {{obj.desc}}
        </nb-list>
      </nb-card-body>
    </nb-card>

Thank you for your help!

Answer 1

I think what you are looking for is (either should work)

export class AnalysisComponent implements OnInit {
    //persuadables: Array<{'icon':string, 'desc':string, 'status':string}> = [];
    //persuadables: {'icon':string, 'desc':string, 'status':string}[] = [];
}

Answer 2

I think that happened cause you wrote the type but you not defined array.

Try like this:

export interface Persuadable {
  icon: string;
  desc: string;
  status: string;
}
export class AnalysisComponent implements OnInit {
    public persuadables: Array<Persuadable> = [];
}

Use interfaces and init your array.