let a = []
console.log (a)
a.push (1)
the console shows an empty array,
let a = []
console.log (a)
a.push (1)
the console shows an empty array,
because Array is reference type in js, although you console.log > before push , because reference type is address is not pass value , the array you see in the console will be updated with the subsequent operation of the array
So you can see the value of push after that. In other words, console.log is just a snapshot of that time, so it comes out as an empty array, but it still maintains a connection with memory. When you click expand, the browser reads the value in it from memory in real time. I don't know if you can understand that.
this example fully shows that console.log is asynchronous , so try not to use console to debug your app.
the empty one above is just a snapshot, and the real data is when you click on it.
if you change a to the basic type, you will never have this problem.
the root cause is because it is a reference type wow
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