将 Javascript 数组分配给变量会导致项目从数组中删除

Question

I am experiencing a weird problem where assigning an array to a variable is causing some of the items in the array to be removed. This could potentially be related to Vue.js as well.

I am storing an array of data in localStorage as a string ( since that is all localStorage accepts ). When the user clicks a button within the app it runs a Vue function checking to see if localStorage has a particular key and if so I am assigning that key to a variable 'localCards' within the function. When the localStorage data gets assigned to the variable it is dropping some of the items in the array. Below is a sample of the code for a better understanding:

console.log( JSON.parse(localStorage.getItem('localCards')) );
// Returns the complete array

let localCards = JSON.parse(localStorage.getItem('localCards'));
console.log( localCards );
// Returns the first two items in the array

Any idea why assigning the data to a variable is dropping some of the items?

Answer 1

It turns out that this was happening because the array was being mutated later in the code. I was not aware that it would affect logging prior to the mutation as pointed out by @skirtle in the comments above.

Answer 2

i guess you should declare your variable first...as an array; then parse it

var localCards =[];
localCards =JSON.parse(localStorage.getItem('localCards'));