Fix default param values with implied this param

Resolves #2698

CHANGELOG.md

@@ -11,6 +11,7 @@
 -   `@link` tags to symbols which are not included in the documentation will produce invalid link warnings again, #2681.
 -   Fixed handling of `@param` tags on comments attached to function callback parameters, #2683.
 -   The `alphabetical` and `alphabetical-ignoring-documents` sort options now use `localeCompare` to sort, #2684.
+-   Fixed incorrect placement of parameter default values in some signatures with a `this` parameter, #2698.
 
 ## v0.26.6 (2024-08-18)
 

src/lib/converter/factories/signature.ts

@@ -193,6 +193,12 @@ function convertParameters(
         | readonly ts.JSDocParameterTag[]
         | undefined,
 ) {
+    // #2698 if `satisfies` is used to imply a this parameter, we might have
+    // more parameters than parameter nodes and need to shift the parameterNode
+    // access index. Very ugly, but it does the job.
+    const parameterNodeOffset =
+        parameterNodes?.length !== parameters.length ? -1 : 0;
+
     return parameters.map((param, i) => {
         const declaration = param.valueDeclaration;
         assert(
@@ -254,7 +260,9 @@ function convertParameters(
             paramRefl.type = removeUndefined(paramRefl.type);
         }
 
-        paramRefl.defaultValue = convertDefaultValue(parameterNodes?.[i]);
+        paramRefl.defaultValue = convertDefaultValue(
+            parameterNodes?.[i + parameterNodeOffset],
+        );
         paramRefl.setFlag(ReflectionFlag.Optional, isOptional);
 
         // If we have no declaration, then this is an implicitly defined parameter in JS land
@@ -268,7 +276,10 @@ function convertParameters(
         }
 
         paramRefl.setFlag(ReflectionFlag.Rest, isRest);
-        checkForDestructuredParameterDefaults(paramRefl, parameterNodes?.[i]);
+        checkForDestructuredParameterDefaults(
+            paramRefl,
+            parameterNodes?.[i + parameterNodeOffset],
+        );
         return paramRefl;
     });
 }

src/test/converter2/issues/gh2698.ts

@@ -0,0 +1,21 @@
+type Square = {
+    color: "red" | "blue" | "green";
+};
+
+type TAnimator = {
+    (
+        this: Square,
+        numSpins: number,
+        direction: "clockwise" | "counterclockwise",
+    ): string;
+};
+
+export const animator = function (
+    numSpins: number = 2,
+    direction: "clockwise" | "counterclockwise" = "counterclockwise",
+) {
+    console.log(this.color, numSpins, direction);
+    return "Hello World";
+} satisfies TAnimator;
+
+animator.call({ color: "blue" }, 77);

src/test/issues.c2.test.ts

@@ -1707,4 +1707,18 @@ describe("Issue Tests", () => {
         // had a chance to copy the data's @param to the parameter.
         equal(data2.comment, undefined);
     });
+
+    it("#2698 handles this parameters present in type but not node", () => {
+        const project = convert();
+        const animator = querySig(project, "animator");
+        equal(
+            animator.parameters?.map((p) => p.name),
+            ["this", "numSpins", "direction"],
+        );
+
+        equal(
+            animator.parameters.map((p) => p.defaultValue),
+            [undefined, "2", '"counterclockwise"'],
+        );
+    });
 });