1
// Copyright (c) 2022-2023 Cloudflare, Inc.
2
// Licensed under the Apache 2.0 license found in the LICENSE file or at:
3
//     https://opensource.org/licenses/Apache-2.0
4
 
5
import assert from "assert";
6
import { test } from "node:test";
7
import path from "path";
8
import ts from "typescript";
9
import { printer } from "../../src/print";
10
import { createMemoryProgram } from "../../src/program";
11
import { createClassToInterfaceTransformer } from "../../src/transforms/class-to-interface";
12
 
13
test("createClassToInterfaceTransformer: transforms class to interface", () => {
14
  const source = `
15
    class MyClass<T = void, U = void> {
16
      constructor(str: string): MyClass;
17
      prop: T;
18
      method(): U {}
19
      get accessor(): number { return 42; }
20
      static staticMethod(str?: string): void {}
21
      private privateMethod() {}
22
    }
23
  `;
24
 
25
  const expectedOutput = `
26
    declare var MyClass: {
27
      prototype: MyClass;
28
      new <T = void, U = void>(str: string): MyClass<T, U>;
29
      staticMethod(str?: string): void;
30
    };
31
    interface MyClass<T = void, U = void> {
32
      prop: T;
33
      method(): U;
34
      accessor: number;
35
    }
36
  `;
37
 
38
  const sourcePath = path.resolve(__dirname, "source.ts");
39
  const sources = new Map([[sourcePath, source]]);
40
  const program = createMemoryProgram(sources);
41
  const sourceFile = program.getSourceFile(sourcePath);
42
  assert(sourceFile !== undefined);
43
 
44
  const result = ts.transform(sourceFile, [
45
    createClassToInterfaceTransformer(["MyClass"]),
46
  ]);
47
  assert.strictEqual(result.transformed.length, 1);
48
 
49
  const output = printer.printFile(result.transformed[0]);
50
  assert.strictEqual(
51
    normalizeWhitespace(output.trim()),
52
    normalizeWhitespace(expectedOutput.trim()),
53
    "The transformed output did not match the expected output"
54
  );
55
});
56
 
57
function normalizeWhitespace(str: string) {
58
  return str.replace(/\s+/g, " ").trim();
59
}