Linting error: Move this array "sort" operation to a separate statement

Question

Could you please help to fix linting error with below javascript function.

Error: Move this array "sort" operation to a separate statement.

  item.EmployeeDetails = item.EmployeeDetails
                            .sort((a: IEmployeeDetails, b: IEmployeeDetails) => {
        if (a.employeeType < b.employeeType) {
            return 1;
        }
        if (a.employeeType > b.employeeType) {
            return -1;
        }
        return 0;
    });

Answer 1

sort() mutates the array. See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype#Mutator_methods

So, try to omit the assignment operator:

item.EmployeeDetails.sort((a: IEmployeeDetails, b: IEmployeeDetails) => {
    if (a.employeeType < b.employeeType) {
        return 1;
    }
    if (a.employeeType > b.employeeType) {
        return -1;
    }
    return 0;
});

Answer 2

In order to resolve this, you have to copy the original array before sorting. This is because sorting mutates the original array. You can read more about this linting error here: https://rules.sonarsource.com/typescript/RSPEC-4043

const sortedEmployeeDetails = [...item.EmployeeDetails]
                                .sort((a: IEmployeeDetails, b: IEmployeeDetails) => {
            if (a.employeeType < b.employeeType) {
                return 1;
            }
            if (a.employeeType > b.employeeType) {
                return -1;
            }
            return 0;
        });