如何用新项目替换局部存储项目

Question

我们尝试在LocalStorage中设置一个新项目。但是，只有更高的是最后一项。我们的问题是，如果比较不起作用。有什么想法吗？

对不起，如果我们问一个愚蠢的问题，但是我们只是初学者寻求帮助。非常感谢。

 saveList(){
 let newScore:any; //this is a numeric value pushed from another page
 newScore=this.newlist;

 localStorage.setItem("scores", (newScore));
 parseInt(localStorage.getItem( "score")) ;

 let highscore= parseInt( localStorage.getItem("scores"));

 if(newScore>highscore){ 
  localStorage.setItem("scores", (newScore));

}
  //let storedScores = JSON.parse(localStorage.getItem("scores"));   
}

Answer 1

因为localstorage.getItem((将返回null如果本地存储中没有对象，则可以使用此

saveList(){
 let newScore:any;  
 newScore=this.newlist;
 let highscore= parseInt( localStorage.getItem("scores")); 
 if(  highscore > newScore ){
  // do nothing 
 } else  { 
    localStorage.setItem("scores", (newScore));
  }
}

Answer 2

您可以使用三元操作

saveList(){
    let newScore=this.newlist;
    let highscore= parseInt( localStorage.getItem("scores")); 
    localStorage.setItem("scores", ((newScore>highscore) ? newScore : highscore));
}   

Answer 3

您可以考虑使用相同的密钥替换本地项目，例如...

var boo = "my boo"
var newBoo = "my new boo"
localStorage.setItem("foo", boo);        // foo: "my boo"
// replacing...
localStorage.setItem("foo", newBoo);     // foo: "my new boo"