我怎样才能正确地传播这些阵列？

Question

I need to insert an empty item as the first item in an array of data which will be databound to a dropdown. My code looks like this:

      let suppliers = response.data[0];
      let defaultSupplier = [{ SupplierId:0, ContactFirstName:''}];
      suppliers = [...defaultSupplier, suppliers];

I was thinking that this code would initialize my array with a default item, and then I could simply spread the retrieved suppliers data into this array. However, the result of this approach is that I have an array where defaultSupplier is the first item in the array and then the second item in the array is an array of the retrieved supplier data. What approach do I need to take so that the retrieved suppliers data is appended at the same level as the defaultSupplier?

Answer 1

You have to spread suppliers . But you created new array defaultSupplier with one element and spread this one. Correct variant:

let suppliers = response.data[0]; // array
let defaultSupplier = { SupplierId:0, ContactFirstName:''};
suppliers = [defaultSupplier, ...suppliers]; // spread array suppliers

Answer 2

defaultSupplier and supplier are both array of objects.

so, you need to spread both arrays into new array like this

 suppliers = [...defaultSupplier, ...suppliers];