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title | summary |
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Adding arguments | Add arguments to your fields, queries, and mutations |
Working with generic types
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Adding arguments
Fields can have arguments, and queries are just fields, so let's add a simple way of influencing our query response:
app/_graphql/schema.yml
queries:
'readCountries(limit: Int!)': '[Country]'
We've provided the required argument limit
to the query, which will allow us to truncate the results.
Let's update the resolver accordingly.
public static function resolveReadCountries($obj, array $args = [])
{
$limit = $args['limit'];
$results = [];
$countries = Injector::inst()->get(Locales::class)->getCountries();
$countries = array_slice($countries, 0, $limit);
foreach ($countries as $code => $name) {
$results[] = [
'code' => $code,
'name' => $name
];
}
return $results;
}
Now let's try our query again. This time, notice that the IDE is telling us we're missing a required argument.
query {
readCountries(limit: 5) {
name
code
}
}
This works pretty well, but maybe it's a bit over the top to require the limit
argument. We want to optimise
performance, but we also don't want to burden the developer with tedium like this. Let's give it a default value.
app/_graphql/schema.yml
queries:
'readCountries(limit: Int = 20)': '[Country]'
Rebuild the schema, and notice that the IDE is no longer yelling at you for a limit
argument.
Let's take this a step further by turning this in to a proper paginated result.
Further reading
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