feat: switch DataFrame generic to its schema

__tests__/type.test.ts

@@ -0,0 +1,78 @@
+import { expectType } from "ts-expect";
+
+import {
+  DataFrame,
+  type Float64,
+  type Int64,
+  type String as PlString,
+  type Series,
+} from "../polars";
+
+describe("type tests", () => {
+  it("is cleaned up later", () => {
+    const a = null as unknown as DataFrame<{
+      id: Int64;
+      age: Int64;
+      name: PlString;
+    }>;
+    const b = null as unknown as DataFrame<{
+      id: Int64;
+      age: Int64;
+      fl: Float64;
+    }>;
+    expectType<Series<Int64, "age">>(a.getColumn("age"));
+    expectType<
+      (Series<Int64, "id"> | Series<Int64, "age"> | Series<PlString, "name">)[]
+    >(a.getColumns());
+    expectType<DataFrame<{ id: Int64; age: Int64 }>>(a.drop("name"));
+    expectType<DataFrame<{ id: Int64 }>>(a.drop(["name", "age"]));
+    expectType<DataFrame<{ id: Int64 }>>(a.drop("name", "age"));
+    // expectType<Series<Int64, "age">>(a.age);
+    expectType<
+      DataFrame<{
+        id: Int64;
+        age: Int64;
+        age_right: Int64;
+        name: PlString;
+        fl: Float64;
+      }>
+    >(a.join(b, { on: ["id"] }));
+    expectType<
+      DataFrame<{
+        id: Int64;
+        age: Int64;
+        ageRight: Int64;
+        name: PlString;
+        fl: Float64;
+      }>
+    >(a.join(b, { on: ["id"], suffix: "Right" }));
+    expectType<
+      DataFrame<{
+        id: Int64;
+        id_right: Int64;
+        age: Int64;
+        name: PlString;
+        fl: Float64;
+      }>
+    >(a.join(b, { leftOn: "id", rightOn: ["age"] }));
+    expectType<
+      DataFrame<{
+        id: Int64;
+        id_right: Int64;
+        age: Int64;
+        age_right: Int64;
+        name: PlString;
+        fl: Float64;
+      }>
+    >(a.join(b, { how: "cross" }));
+  });
+
+  it("folds", () => {
+    const df = DataFrame({
+      a: [2, 1, 3],
+      b: [1, 2, 3],
+      c: [1.0, 2.0, 3.0],
+    });
+    expectType<Series<Float64, string>>(df.fold((s1, s2) => s1.plus(s2)));
+  });
+});

package.json

@@ -62,6 +62,7 @@
     "chance": "^1.1.12",
     "jest": "^29.7.0",
     "source-map-support": "^0.5.21",
+    "ts-expect": "^1.3.0",
     "ts-jest": "^29.2.5",
     "ts-node": "^10.9.2",
     "typedoc": "^0.27.3",