feat: make resolved ProcessPromise iterable

[Pulkit1822]

Added a synchronous iterator to the ProcessOutput class to allow iterating over stdout lines.

• src/core.ts

  • Added a synchronous iterator method [Symbol.iterator]() to the ProcessOutput class.
  • Split the stdout string into lines using \r?\n to handle both Unix and Windows line endings.
  • Returned the iterator of the split array.

• test/core.test.js

  • Added a test case to verify the synchronous iterator method in the ProcessOutput class.
  • Also ensured that the test case covers both Unix and Windows line endings.

[antongolub]

@Pulkit1822, not so fast)

1. ProcessOutput has already lines() extractor, it should be used here.
2. ProcessPromise, if resolved, should apply generator around its internal data.

{
  [Symbol.iterator]: function* () {
    yield* this._output.lines()
  }
}

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterable_protocol

[Pulkit1822]

@antongolub, As per suggestions, I’ve added the iterable protocol in core.ts with this.lines()[Symbol.iterator](), so ProcessOutput can be used in for...of loops. The test in core.test.js checks that ProcessOutput gives the correct lines when spread with [ ... ], making sure iterable operations work.

Is this the right way, or should I use:

*[Symbol.iterator](): Iterator<string> {
  yield* this.lines();
}

This would make it a generator function, which seems clearer. Let me know if you have any advice or suggestions.