---
name: "GraphQL::Role::HashMappable"
section: "3pm"
platform: "linux"
package: "libgraphql-perl"
version: "0.54-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/GraphQL::Role::HashMappable"
---

# GraphQL::Role::HashMappable(3pm)

GraphQL object role

## NAME

GraphQL::Role::HashMappable - GraphQL object role

## SYNOPSIS

```
  with qw(GraphQL::Role::HashMappable);
  # or runtime
  Role::Tiny->apply_roles_to_object($foo, qw(GraphQL::Role::HashMappable));
```

## DESCRIPTION

Provides method for mapping code over a hash-ref.

## METHODS

### hashmap

Given a hash-ref, returns a modified copy of the data. Returns undef if given that. Parameters:

- $item

  Hash-ref.

- $source

  Hash-ref of the source data for this hash. Will be used only for its keys.

- $code

  Code-ref.

Each value will be the original value returned by the given code-ref, which is called with `$keyname`, `$value`. Will call the code for all given keys, but not copy over any values not existing in original item.

If code throws an exception, the message will have added to it information about which data element caused it.