Replace array entry with spread syntax in one line of code?

Question

I\'m replacing an item in a react state array by using the ... spread syntax. This works:

let newImages = [...this.state.images]
newImages[4] = updatedImage
this         


        

Answer 1

Here is my self explaning non-one-liner

 const wantedIndex = 4;
 const oldArray = state.posts; // example

 const updated = {
     ...oldArray[wantedIndex], 
     read: !oldArray[wantedIndex].read // attributes to change...
 } 

 const before = oldArray.slice(0, wantedIndex); 
 const after = oldArray.slice(wantedIndex + 1);

 const menu = [
     ...before,  
     updated,
     ...after
 ]