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  "prompt": "Add a splitBill(items, people) function to the cart module that splits the cart total (including tax) between people and returns an array of each person's share.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`. `npm run check` passes, including the lint step and all 5 tests.\n\n- **How it splits:** It divides `total(items)`, tax included, across `people`. It rounds each share with `roundCents()`, as the lint step requires. Any leftover cent goes to a later share, so the shares always add up exactly to the total. They differ from each other by at most one cent.\n- **Invalid input:** It throws a `RangeError` if `people` isn't a positive integer.\n- **Tests and changelog:** I wrote the tests first in `tests/lib/cart.test.js`, covering an even split, shares that sum to the total (10 split three ways), and the invalid-count errors. I also added a line to `CHANGES.md` under Unreleased.\n\nI haven't committed anything.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`. `npm run check` passes, including the money-rounding lint and all 6 tests. I wrote the tests first and watched them fail before adding the function.\n\n- **People:** `people` can be a head count or an array of people.\n- **Invalid input:** it throws a `RangeError` for anything that isn't a whole number of at least 1, including an empty array.\n- **Shares:** it splits `total(items)`, so tax is included. Everyone pays an equal share rounded to cents. The last person pays whatever is left, so the shares always add up to the total. For example, `splitBill([{price: 0.1, qty: 1}], 3)` splits 0.11 into 0.04, 0.04 and 0.03.\n- **Rounding:** all rounding goes through `roundCents()`, as the lint rule requires.\n\nI also added a line to `CHANGES.md` under Unreleased. I haven't committed anything.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`. `npm run check` passes: the lint step is ok and all 6 tests pass.\n\n- **How it splits:** it takes `total(items)`, which includes tax, and splits it in whole cents, so the shares always add up exactly to the total. Any leftover cents go one each to the first people. For example, 27.00 split 7 ways gives five shares of 3.86 and two of 3.85.\n- **`people` is a count:** it must be a positive integer, and anything else throws a `RangeError`. If you meant `people` to be an array of names or objects, the signature needs to change, so tell me.\n- **Rounding:** it uses `roundCents()` from `money.js`, as the lint rule requires.\n- **Tests and changelog:** I wrote the tests first in `tests/lib/cart.test.js` and added a line under Unreleased in `CHANGES.md`. One of my first test expectations had the wrong split for 7 people. The code was right, so I corrected the test.\n\nI haven't committed anything.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`. All 7 tests pass, and `npm run check` passes too, including the repo's lint for money rounding.\n\n**Tests first:** I wrote the new tests in `tests/lib/cart.test.js` and ran them before implementing. The test file failed because `splitBill` didn't exist yet.\n\n**How it works:**\n- **Total:** it splits `total(items)`, which includes tax, in whole cents.\n- **Leftover cents:** when the total doesn't divide evenly, the first people each get one extra cent. The shares always add up to exactly the total. For example, a one-cent bill split three ways gives `[0.01, 0, 0]`.\n- **`people`:** it accepts either a head count or an array of people. I added the array form on my own, so say if you'd rather it take only a number.\n- **Invalid input:** it throws a `RangeError` for zero, negative or fractional counts, and for an empty array.\n\n**Edge cases tested:** an even split, a single person, uneven splits where the shares must sum to the total, an array of people, an empty cart (all zeros), and the invalid inputs above.\n\nThe lint bans `Math.round`, `Math.floor` and `toFixed` outside `money.js`. I used `Math.trunc` and `roundCents()` instead.\n\nI also added a line to `CHANGES.md` under Unreleased. I haven't committed anything.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`, and `npm run check` passes (lint plus all 10 tests).\n\nI wrote the tests first and ran them. They failed because `splitBill` wasn't exported yet. After implementing it, they all pass.\n\n- **Splitting:** the function splits `total(items)`, which includes tax, in whole cents. Any leftover cents go one each to the first people, so the shares always add up exactly to the total. For example, a 1.09 total across 3 people gives `[0.37, 0.36, 0.36]`.\n- **`people` argument:** you didn't say whether it's a list or a number, so it accepts either an array of people or a head count.\n- **Invalid input:** it throws a `RangeError` for 0, negative, fractional or `NaN` counts, an empty array, or `undefined`.\n- **Rounding:** it rounds through `roundCents`, as the lint rule requires.\n- **Tests:** they cover an even split, a single person, a head count, uneven cents, shares summing to the total, an empty cart (all zero shares), more people than cents, and the invalid inputs.\n\nI also added a line for it under \"Unreleased\" in `CHANGES.md`. Nothing is committed.",
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      "finalMessage": "I added `splitBill(items, people)` to `src/lib/cart.js`, and `npm run check` (lint plus all 9 tests) now passes.\n\n**How it works:** it splits the taxed total (from `total()`) in whole cents. Any leftover cents go one each to the first people, so the shares always add up exactly to the total. For example, 0.11 split four ways gives `[0.03, 0.03, 0.03, 0.02]`. `people` can be a headcount or an array of people. A non-positive-integer count or an empty array throws a `RangeError`. An empty cart gives all zeros.\n\n**Tests-first:**\n- I wrote 7 new tests in `tests/lib/cart.test.js`. They cover an even split, an array of people, one person, leftover cents, the first-people rule, an empty cart and invalid input.\n- The first run failed, because `splitBill` wasn't exported yet.\n- After implementing, one test still failed. The code was right and my expected values were wrong (0.10 plus tax is 0.11, not 0.10). I corrected the test, not the code.\n\nI also added a line to `CHANGES.md`. Nothing is committed.",
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  "finishedAt": "2026-10-17T01:58:28.923Z"
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