角2無法讀取屬性未定義

Question

我有一個簡單的搜索文本框和值改變，我在調用這個函數（我用Lodash）

onKeyCustomerSearch(event: any) { 

    this.SearchCustomerString = event.target.value; 

    this.customersView = _.clone(this.customersArray); 
    this.customersView.paginatedCustomers = _.filter(this.customersView.paginatedCustomers, function (x) { 
     return x.BusinessName.includes(this.SearchCustomerString); 
    }); 
    } 

我越來越無法讀取的不確定

財產「SearchCustomerString」

但是，這是工作！

onKeyCustomerSearch(event: any) { 

    this.customersView = _.clone(this.customersArray); 
    this.customersView.paginatedCustomers = _.filter(this.customersView.paginatedCustomers, function (x) { 
     return x.BusinessName.includes(event.target.value); 
    }); 
    } 

Answer 1

而不是使用函數表達式（FE）我會用箭頭功能()=>保留this的：

this.customersView.paginatedCustomers = _.filter(this.customersView.paginatedCustomers, 
          (x) => x.BusinessName.includes(this.SearchCustomerString)); 

又見

• https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions#No_binding_of_this