aoc-kit is a Node library / CLI built for Advent of Code. It takes care of downloading your specific program input for each task and enables automatic submission of your answers.
To install aoc-kit into your project, use your preferred package manger. In case of npm, run the following command:
npm install aoc-kit
This will allow you to import the defineSolution() method from within your code. However, you still need a way to run the CLI itself. You can do this by also installing the aoc-kit package globally after which you'll be able to execute commands by running:
aoc-kit [command] [args]
Alternatively, you can execute these commands without installing the package globally by prefixing them with npx and running them inside your project directory (e.g. npx aoc-kit run index.js).
While there are multiple features of this tool that are able to function anonymously, the actual download of your custom input and submission of your answers will require authentication of your Advent of Code account.
In order to do that, you'll first need to obtain your session token. Start by visiting the official AoC website in your browser and logging into your account. Once logged in, inspect the website's cookies in your browser's developer tools. There, you should be able to see a cookie named session. Its value is the session token you're looking for.
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| Session token example in Chrome DevTools |
Once you have the token, authenticate your account in the CLI by running:
aoc-kit login [token]
Analogically, you can also run aoc-kit logout to remove your account's authentication from the CLI.
When writing a solution, start by creating a .js (or .mjs) file with the following contents:
import { defineSolution } from 'aoc-kit';
export default defineSolution((input, solve, config) => {}, {});Let's start off by focusing on the second argument of our defineSolution() method. This argument is a configuration object for how the CLI is supposed to behave while executing our code and is entirely optional as well as any of its properties. The supported properties are:
| property | type | description |
|---|---|---|
| mode | 'text' | 'lines' | 'numbers' |
Sets up how the input is pre-processed before being passed to your solution. In text mode, it is passed directly as a string. In lines mode, the content gets split by lines and passed in the form of a string[]. numbers mode works similarly to lines mode but each line also gets automatically converted into a number. In this case, the input is of type number[]. |
| example | boolean |
If set to true, the program isn't going to use your actual input for the given task but the example given on the AoC website instead. This is useful for development and debugging and does not require account authentication. It's not possible to submit an answer while using the example input. Defaults to false. |
| year | number |
The year of AoC we're writing a solution for. Defaults to whatever is currently the latest year of AoC. |
| day | number |
The day of AoC we're writing a solution for. Accepts values from 1 to 25. |
| part | number |
Part of the specified day of AoC we're writing a solution for. Accepts values 1 or 2. |
Most of these properties can also be set in the form of a CLI argument, instead of making them part of the JS code (more in the CLI Options section). If the same property is set in both places, the CLI argument serves as an override.
Now let's take a look at the first argument of the defineSolution() method. This one is a function whose body will contain our actual solution to the given task and it takes different 3 arguments. The first one named input contains the input data for the task and is either of type string or string[], depending on the lines property of our configuration object as described above.
The second argument is a function called solve(). This is a function we'll most likely be calling at the very end of our solution's code and its argument is the value we desire to submit as our final answer. The argument can either be of type string or number. This function must be called exactly once during the execution of our solution.
The last argument is an object named config. This object contains the entire configuration of the CLI during this execution. It combines values from the configuration object passed into the defineSolution() method as well as any overrides cause by additional CLI arguments. Its properties are mostly the same as in the case of the configuration object with the exception of a new input property of type string | null which contains the value passed with the --input flag of the CLI (more in the CLI Options section).
| Command | Description |
|---|---|
aoc‑kit login [token] |
Authenticates user account with the CLI (more in the Configuration section) |
aoc‑kit run [src_file] |
Executes the specified solution but only prints the answer. It doesn't try submitting it to the AoC server. Use this command during development. Additional flags for this command specified beflow. |
aoc‑kit submit [src_file] |
Executes the specified solution and submits the answer to the AoC server. Additional flags for this command specified beflow. |
aoc‑kit logout |
Logs user out from the CLI (more in the Configuration section) |
aoc‑kit clear |
Clears all data stored by aoc-kit (input file cache and login information) |
CLI flags for the aoc-kit run and aoc-kit submit comnmands:
| Flag | Argument | Description |
|---|---|---|
‑‑year, ‑y |
number | Override for the year property of the configuration object (more in the Usage section) |
‑‑day, ‑d |
number | Override for the day property of the configuration object (more in the Usage section) |
‑‑part, ‑p |
number | Override for the part property of the configuration object (more in the Usage section) |
‑‑example, ‑e |
‑none‑ | Override for the example property of the configuration object (more in the Usage section). This flag doesn't take an argument. It's presence sets the example property to true. This flag cannot be used with aoc‑kit submit. |
‑‑input, ‑i |
filepath | When this flag is set, the CLI loads input for the task from a specified file (path relative to the working directory of your terminal). This flag cannot be used with aoc‑kit submit. When this flag is set, the example property is ignored and the day and part properties don't have to be set. |
main.js:
import { defineSolution } from 'aoc-kit';
// Sums up all numbers in the input
export default defineSolution((input, solve) => {
const nums = input.map(x => Number(x));
const sum = nums.reduce((acc, x) => x + acc, 0);
solve(sum);
}, { mode: 'lines' });Terminal:
$ aoc-kit submit -y 1984 -d 3 -p 1 main.js
√ Input fetched from network
√ Solution module loaded
► Your answer: 4726
------------------------------------------
√ Solution successfully submitted
√ Your answer was CORRECT
✶ DAY 3 (Part 1) OF 1984 COMPLETED ✶
MIT