Imagine a scenario where we have a set of simple nodes/objects forming a tree structure, each with parent and children references. The challenge lies in the need to reference both the parent and children nodes independently from the tree itself. This means we cannot directly nest them within their parent nodes but must establish references to link them together. This complex setup leads to a Typescript error:
2448 Block-scoped variable 'rootNode' used before its declaration.ts(2448)
If we arrange the nodes in descending order, we can reference the children above but not the parents below, and vice versa if parents are placed above children. This causes difficulties as Typescript does not appear to handle pre-compiling declarations effectively, resulting in errors.
So how do we resolve this issue?
Below is an example illustrating the tree nodes (organized in descending order) along with their 'independent' nodes containing references:
export interface Node {
id: string,
value?: string,
parent?: Node,
children?: Node[]
}
export const nodeB2: Node = {
id: 'B2',
value: 'bbb-2',
parent: nodeA1 // ERROR 2448
}
export const nodeB1: Node = {
id: 'B1',
value: 'bbb-1',
parent: nodeA1 // ERROR 2448
}
export const nodeA1: Node = {
id: 'A1',
value: 'aaa-1',
parent: rootNode, // ERROR 2448
children: [nodeB1, nodeB2]
}
export const rootNode: Node = {
id: 'ROOT',
value: 'root',
children: [nodeA1]
}