feat: expose findAncestor. (microsoft#40325)

* feat: add closest node util

* chore: add definition to baseline file

* chore: alias findAncestor to getClosestNode

* move findAncestor to public

* move findAncestor to public

Author: septs

src/compiler/utilities.ts

@@ -100,28 +100,6 @@ namespace ts {
             !isJsonEqual(getCompilerOptionValue(oldOptions, o), getCompilerOptionValue(newOptions, o)));
     }
 
-    /**
-     * Iterates through the parent chain of a node and performs the callback on each parent until the callback
-     * returns a truthy value, then returns that value.
-     * If no such value is found, it applies the callback until the parent pointer is undefined or the callback returns "quit"
-     * At that point findAncestor returns undefined.
-     */
-    export function findAncestor<T extends Node>(node: Node | undefined, callback: (element: Node) => element is T): T | undefined;
-    export function findAncestor(node: Node | undefined, callback: (element: Node) => boolean | "quit"): Node | undefined;
-    export function findAncestor(node: Node, callback: (element: Node) => boolean | "quit"): Node | undefined {
-        while (node) {
-            const result = callback(node);
-            if (result === "quit") {
-                return undefined;
-            }
-            else if (result) {
-                return node;
-            }
-            node = node.parent;
-        }
-        return undefined;
-    }
-
     export function forEachAncestor<T>(node: Node, callback: (n: Node) => T | undefined | "quit"): T | undefined {
         while (true) {
             const res = callback(node);

src/compiler/utilitiesPublic.ts

@@ -403,6 +403,28 @@ namespace ts {
         return !nodeTest || nodeTest(node) ? node : undefined;
     }
 
+    /**
+     * Iterates through the parent chain of a node and performs the callback on each parent until the callback
+     * returns a truthy value, then returns that value.
+     * If no such value is found, it applies the callback until the parent pointer is undefined or the callback returns "quit"
+     * At that point findAncestor returns undefined.
+     */
+    export function findAncestor<T extends Node>(node: Node | undefined, callback: (element: Node) => element is T): T | undefined;
+    export function findAncestor(node: Node | undefined, callback: (element: Node) => boolean | "quit"): Node | undefined;
+    export function findAncestor(node: Node, callback: (element: Node) => boolean | "quit"): Node | undefined {
+        while (node) {
+            const result = callback(node);
+            if (result === "quit") {
+                return undefined;
+            }
+            else if (result) {
+                return node;
+            }
+            node = node.parent;
+        }
+        return undefined;
+    }
+
     /**
      * Gets a value indicating whether a node originated in the parse tree.
      *

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -4050,6 +4050,14 @@ declare namespace ts {
     function getOriginalNode<T extends Node>(node: Node, nodeTest: (node: Node) => node is T): T;
     function getOriginalNode(node: Node | undefined): Node | undefined;
     function getOriginalNode<T extends Node>(node: Node | undefined, nodeTest: (node: Node | undefined) => node is T): T | undefined;
+    /**
+     * Iterates through the parent chain of a node and performs the callback on each parent until the callback
+     * returns a truthy value, then returns that value.
+     * If no such value is found, it applies the callback until the parent pointer is undefined or the callback returns "quit"
+     * At that point findAncestor returns undefined.
+     */
+    function findAncestor<T extends Node>(node: Node | undefined, callback: (element: Node) => element is T): T | undefined;
+    function findAncestor(node: Node | undefined, callback: (element: Node) => boolean | "quit"): Node | undefined;
     /**
      * Gets a value indicating whether a node originated in the parse tree.
      *

tests/baselines/reference/api/typescript.d.ts

@@ -4050,6 +4050,14 @@ declare namespace ts {
     function getOriginalNode<T extends Node>(node: Node, nodeTest: (node: Node) => node is T): T;
     function getOriginalNode(node: Node | undefined): Node | undefined;
     function getOriginalNode<T extends Node>(node: Node | undefined, nodeTest: (node: Node | undefined) => node is T): T | undefined;
+    /**
+     * Iterates through the parent chain of a node and performs the callback on each parent until the callback
+     * returns a truthy value, then returns that value.
+     * If no such value is found, it applies the callback until the parent pointer is undefined or the callback returns "quit"
+     * At that point findAncestor returns undefined.
+     */
+    function findAncestor<T extends Node>(node: Node | undefined, callback: (element: Node) => element is T): T | undefined;
+    function findAncestor(node: Node | undefined, callback: (element: Node) => boolean | "quit"): Node | undefined;
     /**
      * Gets a value indicating whether a node originated in the parse tree.
      *