E0708: unexpected '...'; expected expression
The spread ('...') operator must precede an expression:
const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arr3 = [...arr1, ...];
To fix this error, insert a valid expression after the operator:
const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const arr3 = [...arr1, ...arr2];