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 { createIteratorTransformer } from "../../src/transforms";
12
 
13
test("createIteratorTransformer: replaces Iterator-like interfaces with built-in Iterators", () => {
14
  const source = `export class Thing {
15
    readonly thingsProperty: ThingIterator;
16
    readonly asyncThingsProperty: AsyncThingIterator;
17
    things(): ThingIterator;
18
    asyncThings(): AsyncThingIterator;
19
    [Symbol.iterator](): ThingIterator;
20
    [Symbol.asyncIterator](): AsyncThingIterator;
21
}
22
export interface ThingIterator extends Iterator {
23
    next(): ThingIteratorNext;
24
    [Symbol.iterator](): any;
25
}
26
export interface ThingIteratorNext {
27
    done: boolean;
28
    value?: string;
29
}
30
export interface AsyncThingIterator extends AsyncIterator {
31
    next(): Promise<AsyncThingIteratorNext>;
32
    return(value?: any): Promise<AsyncThingIteratorNext>;
33
    [Symbol.asyncIterator](): any;
34
}
35
export interface AsyncThingIteratorNext {
36
  done: boolean;
37
  value?: number;
38
}
39
`;
40
  const sourcePath = path.resolve(__dirname, "source.ts");
41
  const sources = new Map([[sourcePath, source]]);
42
  const program = createMemoryProgram(sources);
43
  const checker = program.getTypeChecker();
44
  const sourceFile = program.getSourceFile(sourcePath);
45
  assert(sourceFile !== undefined);
46
 
47
  const result = ts.transform(sourceFile, [createIteratorTransformer(checker)]);
48
  assert.strictEqual(result.transformed.length, 1);
49
 
50
  const output = printer.printFile(result.transformed[0]);
51
  assert.strictEqual(
52
    output,
53
    `export class Thing {
54
    readonly thingsProperty: IterableIterator<string>;
55
    readonly asyncThingsProperty: AsyncIterableIterator<number>;
56
    things(): IterableIterator<string>;
57
    asyncThings(): AsyncIterableIterator<number>;
58
    [Symbol.iterator](): IterableIterator<string>;
59
    [Symbol.asyncIterator](): AsyncIterableIterator<number>;
60
}
61
`
62
  );
63
});