Replace the first element in an array-CodePudding

I want to replace the first element in an array. When I try the following, I get the error below. So I just want to always renew the first element in the array with another one

const changeMainpIC = (e) => {
 const pic = e.target.files[0];
 const copy = pics;
 copy[0] = URL.createObjectURL(pic);
 setPics([copy]);
};

blob:http://localhost:3000/65ea67c6-4afb-473e-b36c-f22799082e69,blob:http://localhost:3000/7cb0ad60-316c-4896-8669-xxxx:1 GET blob:http://localhost:3000/65ea67c6-4afb-473e-b36c-xxx,blob:http://localhost:3000/7cb0ad60-316c-4896-8669-xxxnet::ERR_FILE_NOT_FOUND

CodePudding user response：

I am assuming that you have a state set using the setState() hook. I believe the below should work:

const [pics, setPics] = useState([])

const changeMainpIC = (e) => {
 const pic = e.target.files[0];
 const copy = [...pics]; // using the spread operator to create a copy of the pics array
 copy[0] = URL.createObjectURL(pic); //no need to put copy in square brackets because it is already an array
 setPics(copy);
};