For example, can I do the following:
const execute = (a, c = a.b) => {
// some logic
}
c is the parameter whose default value I want to set, and the default value depends on the first argument.
Can I also do the reverse? (I guess not?)
const execute = (c = a.b, a) => {
// some logic
}
The first form is no problem. It can even infer the type of c from a.b.
const execute1 = (a: { b: number}, c = a.b) => {
console.log(a, c)
}
execute1({ b: 123 }) // { b: 123 }, 123
However, the second one won't work. When c is being assigned, a has not been assigned yet. So the compiler complains at you:
// Error: Parameter 'c' cannot reference identifier 'a' declared after it.(2373)
const execute2 = (c: number = a.b, a: { b: number }) => {
console.log(a, c)
}
