I want to reorder an Array with ES6. For example:
[1,2,3,4,5,6,7,8,9]
When my starting number is 5, I want a new array like this:
[5,6,7,8,9,1,2,3,4].
I am able to fix this by looping, comparing, slicing, glueing the thing back together.
However I've read some interesting array functionality with ES6 that might make this easier. But I'm having trouble putting this into practise.
It can be
let newArr = [...arr.slice(arr.indexOf(5)), ...arr.slice(0, arr.indexOf(5))]
or
let newArr = [...arr];
newArr = [...newArr.splice(arr.indexOf(5)), ...newArr];
So I am not sure this is what you have in mind, but assuming you mean we are starting at 5 because its value (not position if you start counting at 1) is 5, the following should work (though maybe not the newfangled idea you wanted).
var startArr =[1,2,3,4,5,6,7,8,9];
var startIndex=startArr.indexOf(5);//finds 5, if you meant just because it is the 5th. say startArr=5-1
if (startIndex!=-1){
var a1=startArr.slice(startIndex);
var a3=a1.concat(startArr.slice(0,startIndex));
//a3 now contains what you wished for, you may console.log(a3) to see
}
