type operation = 'create' | 'update' | 'delete';
type mutationKey = {
operation: operation;
id: K extends 'delete' | 'update' ? string : undefined; // want this field to be undefined if operation above is 'create'
}
// example 1
const ex1 = {
operation: "create"
}
// example 2
const ex2 = {
operation: "update",
id: "1"
}
当我有条件地在对象中添加operation: "create"或任何其他操作时，有没有办法键入id字段？
在所有现有操作之间使用discriminated unions.这样，添加其他操作就很容易扩展.
interface CreateOperation {
operation: 'create'
}
interface UpdateOperation {
operation: 'update'
id: string
}
interface DeleteOperation {
operation: 'delete'
id: string
}
type Operation =
| CreateOperation
| UpdateOperation
| DeleteOperation
// example 1
const ex1: Operation = {
operation: 'create',
}
// example 2
const ex2: Operation = {
operation: 'update',
id: "1"
}