Html 当我想在数组中添加元素时，角度问题

我有一个动物阵列。我想在另一个数组中加入每种动物的“尊重”字段

我在EspeeAnimalPresenteTMP中推送所有动物的Espee，然后删除重复项并在EspeeAnimalPresente中保存下一个数组

我有一个角度代码：

import { Component, OnInit } from '@angular/core';
import { AnimalService } from "./animal.service";
import { Animal } from "./animal";

@Component({
  selector: 'app-animal',
  templateUrl: './animal.component.html',
  styleUrls: ['./animal.component.css']
})
export class AnimalComponent implements OnInit {

  private animaux:Array<Animal>;
  private especeAnimalPresente:Array<string>;
  private especeAnimalPresenteTmp:Array<string>;
  constructor(private animalService: AnimalService) { }

  ngOnInit() {
    this.recupAllAnimals();
  }

  recupAllAnimals(){
    this.animalService.getAllAnimaux().subscribe(data => {
      this.animaux = data;
      this.recupEspecePresent();
    })

  }

  recupEspecePresent(){
    // if (this.animaux){
      for (let animal of this.animaux) {
          this.especeAnimalPresenteTmp.push(animal.espece);
      }
      this.especeAnimalPresente = this.removeDuplicates(this.especeAnimalPresenteTmp);
    // }
  }

  removeDuplicates(array) {
    let unique = {};
    array.forEach(function(i) {
      if(!unique[i]) {
        unique[i] = true;
      }
    });
    return Object.keys(unique);
  }

}

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有人可以帮我吗？

您必须初始化数组，例如在构造函数中：

constructor(private animalService: AnimalService) {
  this.especeAnimalPresenteTmp = [];
}

---

您需要初始化数组：private-espeeAnimalPresenteTMP:array=[]；

constructor(private animalService: AnimalService) {
  this.especeAnimalPresenteTmp = [];
}