使用Apollo Playground测试使用包含自定义标量的输入Type对象的突变。字段lastWatched是Date的自定义标量类型。也许Date的解析器有问题，或者我只是想不出要在Playground中使用的正确语法。
我的自定义标量称为Date。这是我的Date解析器代码。
注意：由于功能parseLiteral（ast）中的问题，解析器代码已得到纠正。
Date: new GraphQLScalarType({
name: 'Date',
description: 'Date custom scalar type',
parseValue(value) {
console.log('Date scalar parse:', value);
return dayjs(value); // value from the client
},
serialize(value) {
console.log('Date scalar serialize:', value);
return dayjs(value).format('YYYY-MM-DD HH:mm:ss'); // value sent to the client
},
parseLiteral(ast) {
console.log('Date scalar parseLit:', ast);
if (ast.kind === Kind.STRING) {
return dayjs(ast.value).format('YYYY-MM-DD HH:mm:ss') || null; // ast value is always in string format
}
return null;
}
})
我的create突变突变的模式。
extend type Mutation {
createPlaybackPosition(fields: CreatePlaybackPositionInput): PlaybackPositionResponse
updatePlaybackPosition(filename: ID!): PlaybackPositionResponse
deletePlaybackPosition(filename: ID!): PlaybackPositionResponse
}
input CreatePlaybackPositionInput {
"pseudo primary key"
filename: ID!
"in seconds"
position: Int!
"in seconds"
duration: Int!
"date and time (local)"
lastWatched: Date!
}
在Play Play Ground中，该突变看起来像：
mutation {
createPlaybackPosition(
fields: {
filename: "Test Show.S01E01.Piolet"
position: 0
duration: 0
lastWatched: "06/27/2019 14:22:00"
}
) {
success
code
message
validationErrors
}
}
点击播放按钮时出现错误
{
"error": {
"errors": [
{
"message": "Expected type Date!, found \"06/27/2019 14:22:00\"; value is not defined",
"locations": [
{
"line": 2,
"column": 111
}
],
"extensions": {
"code": "GRAPHQL_VALIDATION_FAILED",
"exception": {
"stacktrace": [
"ReferenceError: value is not defined",
" at GraphQLScalarType.parseLiteral (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\src\\resolvers\\common.js:42:44)",
" at isValidScalar (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\validation\\rules\\ValuesOfCorrectType.js:175:28)",
" at Object.StringValue (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\validation\\rules\\ValuesOfCorrectType.js:144:14)",
" at Object.enter (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\language\\visitor.js:332:29)",
" at Object.enter (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\language\\visitor.js:383:25)",
" at visit (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\language\\visitor.js:250:26)",
" at Object.validate (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\graphql\\validation\\validate.js:63:22)",
" at validate (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\apollo-server-core\\dist\\requestPipeline.js:202:32)",
" at Object.<anonymous> (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\apollo-server-core\\dist\\requestPipeline.js:123:42)",
" at Generator.next (<anonymous>)",
" at fulfilled (d:\\Users\\johni\\Projects\\graphql-knex-npvr\\node_modules\\apollo-server-core\\dist\\requestPipeline.js:4:58)",
" at processTicksAndRejections (internal/process/task_queues.js:89:5)"
]
}
}
}
]
}
}
答案 0 :(得分：0)
如果三个标量方法（a，Head和b）中的任何一个返回b，则GraphQL将抛出上述错误。返回Head基本上是一种告诉GraphQL接收到的值无效并且应该抛出验证错误的方法。您不会看到与a相同的行为，因为这是GraphQL中的有效值，但是如果返回def match_lists(a, b, acc \\ [] )
# Case: Element in both lists
def match_lists(
[%{"school" => school, "class" => class, "student" => student} | rest_a],
[%{"school" => school, "class" => class, "choice" => choice} | rest_b],
acc
) do
element = build(school, class, student, [choice], true)
match_lists(rest_a, rest_b, [element | acc])
end
# Case: Element only in list B case. So it is a B case
def match_lists(
[%{"school" => school_a, "class" => class_a} | _] = a,
[%{"school" => school_b, "class" => class_b, "choice" => choice} | rest_b],
acc
)
when school_a > school_b or class_a > class_b do
element = build(school_b, class_b, nil, [choice], "only_list_b")
match_lists(a, rest_b, [element | acc])
end
# Case: No more elementes in A. So It is a B case
def match_lists([], [%{"school" => school, "class" => class, "choice" => choice} | rest_b], acc) do
element = build(school, class, nil, [choice], "only_list_b")
match_lists([], rest_b, [element | acc])
end
# Case: Element only in list A
def match_lists(
[%{"school" => school_a, "class" => class_a, "student" => student} | rest_a],
[%{"school" => school_b, "class" => class_b} | _] = b,
acc
)
when school_b > school_a or class_b > class_a do
element = build(school_a, class_a, student, [], "only_list_a")
match_lists(rest_a, b, [element | acc])
end
# Case: No more elementes in B. So It is an uncommon A case
def match_lists([%{"school" => school, "class" => class, "student" => student} | rest_a], [], acc) do
element = build(school, class, student, [], "only_list_a")
match_lists(rest_a, [], [element | acc])
end
def match_lists([], [], acc) do
acc
end
defp build(school, class, student, choices, is_common) do
%{
"school" => school,
"class" => class,
"student" => student,
"choices" => choices,
"is_common" => is_common
}
end
，也会出现上述错误。
在这种情况下，您要将iex(1)> match_lists(ordered_a, ordered_b)
[
%{
"choices" => [],
"class" => 6,
"is_common" => "only_list_a",
"school" => "c",
"student" => "jane doe2"
},
%{
"choices" => [],
"class" => 9,
"is_common" => "only_list_a",
"school" => "b",
"student" => "jane1 doe"
},
%{
"choices" => ["maths"],
"class" => 6,
"is_common" => "only_list_b",
"school" => "b",
"student" => nil
},
%{
"choices" => ["science"],
"class" => 9,
"is_common" => "only_list_b",
"school" => "a",
"student" => nil
},
%{
"choices" => ["arts"],
"class" => 1,
"is_common" => true,
"school" => "a",
"student" => "jane doe"
}
]
传递给serialize，但这不是您提供的字符串文字的值-它是ValueNode这样的对象：
parseLiteral因此，您应该执行以下操作：
parseValue如果您想始终返回null（如果值无效），并且永远不会抛出验证错误：
undefined