README.md
# Check Maybe Div By Zero for Gleam
[](https://hex.pm/packages/check_maybe_div_by_zero)
[](https://hexdocs.pm/check_maybe_div_by_zero/)
Gleam does not crash on division by zero.
In effect any literal division by zero in gleam returns a zero. You may opt to
use the stdlib's `int.divide`, `int.modulo`, `int.remainder`, `float.divide` and
`float.modulo` to catch errors instead of assmuing 0.
See following explanations why and what happens:
- <https://tutorial.ponylang.io/gotchas/divide-by-zero.html>
- <https://www.hillelwayne.com/post/divide-by-zero/>
## What does this do
This helper checks gleam code for potential(!) literal division by zero.
It may be 100% fine to run `1 / a` if you know that `a` is never zero.
It may also be fine to run `1 / a` where `a` equals `0` depending on your
requirements.
This checker is for when this is not fine. It allows you to check a code
repository for POTENTIAL literal divison by zero in gleam-land (it does NOT
check Erlang or JS FFI).
## Installation
```sh
gleam add check_maybe_div_by_zero@1
```
## Usage
```sh
gleam run --module check_maybe_div_by_zero
# or explicitly define the src dir to check:
gleam run --module check_maybe_div_by_zero -- src
```
Further documentation can be found at <https://hexdocs.pm/check_maybe_div_by_zero>.
## CI Integration
You may run `gleam run --module check_maybe_div_by_zero` which returns `exit(0)`
if no potential division by zero is found, and `exit(1)` if a potential division
by zero is found. It should thus stop the CI in case a divison by zero is found.
```
jobs:
test-and-no-div-zero:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: erlef/setup-beam@v1
with:
otp-version: "27.0.1"
gleam-version: "1.3.2"
rebar3-version: "3"
- run: gleam deps download
- run: gleam format --check src test
- run: gleam test
- run: gleam run --module check_maybe_div_by_zero -- src
- run: gleam test --target javascript
- run: gleam run --module check_maybe_div_by_zero --target javascript -- src
```
## Targets
- Erlang
- NodeJS
- Deno
## Development
```sh
gleam test # Run the tests
```
