> For the complete documentation index, see [llms.txt](https://radlohead.gitbook.io/typescript-deep-dive/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://radlohead.gitbook.io/typescript-deep-dive/overview/ast/ast-tip-children.md).

# TIP: Visit Children

There is a utility function `ts.forEachChild` that allows you to visit all the child nodes of any Node in the AST.

Here is simplified snippet of the source code to demonstrate how it functions:

```typescript
export function forEachChild<T>(node: Node, cbNode: (node: Node) => T, cbNodeArray?: (nodes: Node[]) => T): T {
        if (!node) {
            return;
        }
        switch (node.kind) {
            case SyntaxKind.BinaryExpression:
                return visitNode(cbNode, (<BinaryExpression>node).left) ||
                    visitNode(cbNode, (<BinaryExpression>node).operatorToken) ||
                    visitNode(cbNode, (<BinaryExpression>node).right);
            case SyntaxKind.IfStatement:
                return visitNode(cbNode, (<IfStatement>node).expression) ||
                    visitNode(cbNode, (<IfStatement>node).thenStatement) ||
                    visitNode(cbNode, (<IfStatement>node).elseStatement);

            // .... lots more
```

Basically, it checks `node.kind` and based on that assumes an interface offered by the `node` and calls the `cbNode` on the children. However, note that this function doesn't call `visitNode` for *all* children (e.g. SyntaxKind.SemicolonToken). If you want *all* the children of a node in the AST just call `.getChildren` member function of the `Node`.

E.g. here is a function that prints the verbose `AST` of a node:

```typescript
function printAllChildren(node: ts.Node, depth = 0) {
    console.log(new Array(depth+1).join('----'), ts.syntaxKindToName(node.kind), node.pos, node.end);
    depth++;
    node.getChildren().forEach(c=> printAllChildren(c, depth));
}
```

We will see a sample usage of this function when we discuss the parser further.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://radlohead.gitbook.io/typescript-deep-dive/overview/ast/ast-tip-children.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.