# `Soundcheck.Check.Warning.PatchWithoutHandleParams`
[🔗](https://github.com/leonqadirie/soundcheck/blob/v0.1.0/lib/soundcheck/check/warning/patch_without_handle_params.ex#L1)

## Basics

> #### This check is disabled by default. {: .neutral}
>
> [Learn how to enable it](`e:credo:config_file.html#checks`) via `.credo.exs`.

This check has a base priority of `high` and works with any version of Elixir.

## Explanation

Flags `push_patch`, `<.link patch={...}>`, and `JS.patch` in a
LiveView that defines no `handle_params/3`, when the path routes back
to that LiveView. A patch keeps the LiveView and calls `handle_params/3`
with the new URL, so LiveView raises `UndefinedFunctionError`.

Before:

    # MyAppWeb.PostLive.Index defines mount/3 and render/1 only
    {:noreply, push_patch(socket, to: ~p"/posts?page=#{page}")}

After:

    def handle_params(params, _uri, socket),
      do: {:noreply, assign(socket, :page, params["page"] || "1")}

Paths resolve to routes as in `PatchToForeignLiveView` (SC701); a
patch whose routes all render another LiveView never reaches this
LiveView's `handle_params/3`, and a path the check cannot resolve is
skipped. A `handle_params/3` injected by a `use` macro counts, because
the check reads the compiled module.

Confidence: high. Tier: semantic (run `mix compile` before `mix credo`).

## Check-Specific Parameters

Use the following parameters to configure this check:

### `:excluded_paths`

  Paths to skip (atoms, binaries as path segments, or regexes).

*This parameter defaults to* `[~r/\/test\//, "test"]`.

### `:strict`

  Unused.

*This parameter defaults to* `false`.

## General Parameters

Like with all checks, [general params](`e:credo:check_params.html`) can be applied.

Parameters can be configured via the [`.credo.exs` config file](`e:credo:config_file.html`).

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*Consult [api-reference.md](api-reference.md) for complete listing*