feat: add Node.hasStructure type guard.

dsherret · Nov 6, 2021 · 0f7d9be · 0f7d9be
1 parent 0e9e916
commit 0f7d9be
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Showing 3 changed files with 29 additions and 3 deletions.
diff --git a/packages/ts-morph/src/compiler/ast/common/Node.ts b/packages/ts-morph/src/compiler/ast/common/Node.ts
@@ -7,7 +7,7 @@ import { getNextMatchingPos, getNextNonWhitespacePos, getPreviousNonWhitespacePo
     replaceSourceFileTextForFormatting, replaceSourceFileTextStraight, hasNewLineInRange } from "../../../manipulation";
 import { WriterFunction } from "../../../types";
 import { getParentSyntaxList, getTextFromStringOrWriter, isStringKind, printNode, PrintNodeOptions, CharCodes } from "../../../utils";
-import { Structure } from "../../../structures";
+import { Structure, Structures } from "../../../structures";
 import { FormatCodeSettings } from "../../tools";
 import { Symbol } from "../../symbols";
 import { Type } from "../../types";
@@ -2120,6 +2120,15 @@ export class Node<NodeType extends ts.Node = ts.Node> {
         return (node as any).getBody?.() != null;
     }
 
+    /**
+     * Gets if the node has a structure.
+     * @param node - Node to check.
+     */
+    static hasStructure<T extends compiler.Node>(node: T): node is T & { getStructure(): Structures; } {
+        // this method is manually maintained
+        return typeof (node as any).getStructure === "function";
+    }
+
     /** Creates a type guard for syntax kinds. */
     static is<TKind extends keyof KindToNodeMappings>(kind: TKind): (node: compiler.Node | undefined) => node is KindToNodeMappings[TKind] {
         return (node: compiler.Node | undefined): node is KindToNodeMappings[TKind] => {

diff --git a/packages/ts-morph/src/compiler/ast/statement/StatementedNode.ts b/packages/ts-morph/src/compiler/ast/statement/StatementedNode.ts
@@ -784,7 +784,7 @@ export function StatementedNode<T extends Constructor<StatementedNodeExtensionTy
         getModuleOrThrow(nameOrFindFunction: string | ((declaration: ModuleDeclaration) => boolean)): ModuleDeclaration {
             return errors.throwIfNullOrUndefined(
                 this.getModule(nameOrFindFunction),
-                () => getNotFoundErrorMessageForNameOrFindFunction("namespace", nameOrFindFunction),
+                () => getNotFoundErrorMessageForNameOrFindFunction("module", nameOrFindFunction),
             );
         }
 

diff --git a/packages/ts-morph/src/tests/compiler/ast/common/nodeTypeGuardsTests.ts b/packages/ts-morph/src/tests/compiler/ast/common/nodeTypeGuardsTests.ts
@@ -1,6 +1,7 @@
 import { expect } from "chai";
 import { assert, IsExact } from "conditional-type-checks";
-import { ClassDeclaration, Node } from "../../../../compiler";
+import { ClassDeclaration, ExpressionStatement, Node } from "../../../../compiler";
+import { Structures } from "../../../../structures";
 import { getInfoFromText } from "../../testHelpers";
 
 describe(nameof(Node), () => {
@@ -48,6 +49,22 @@ describe(nameof(Node), () => {
         });
     });
 
+    describe(nameof(Node.hasStructure), () => {
+        it("should have a structure when it does", () => {
+            const { firstChild } = getInfoFromText<Node>("class MyClass {}");
+            expect(Node.hasName(firstChild)).to.be.true;
+            if (Node.hasStructure(firstChild)) {
+                assert<IsExact<typeof firstChild, Node & { getStructure(): Structures; }>>(true);
+                expect((firstChild.getStructure() as any).name).to.equal("MyClass");
+            }
+        });
+
+        it("should not have a structure when it doesn't", () => {
+            const { firstChild } = getInfoFromText<ExpressionStatement>("func();");
+            expect(Node.hasStructure(firstChild.getExpression().getChildren()[0])).to.be.false;
+        });
+    });
+
     describe(nameof(Node.isNode), () => {
         const { firstChild, project } = getInfoFromText("class MyClass {}");