Having default value for optional boolean parameters makes the logic of function when missing that parameter more evident. When providing a default
value is not possible, it is better to split the function into two with a clear responsibility separation.
Noncompliant code example
function countPositiveNumbers(arr: number[], countZero?: boolean) { // Noncompliant, default value for 'countZero' should be defined
// ...
}
function toggleProperty(property: string, value?: boolean) { // Noncompliant, a new function should be defined
if (value !== undefined) {
setProperty(property, value);
} else {
setProperty(property, calculateProperty());
}
}
Compliant solution
function countPositiveNumbers(arr: number[], countZero = false) {
// ...
}
function toggleProperty(property: string, value: boolean) {
setProperty(property, value);
}
function togglePropertyToCalculatedValue(property: string) {
setProperty(property, calculateProperty());
}
