如何在GraphQL查询中有条件地包含参数? [英] How to conditionally include an argument in a GraphQL query?

问题描述

我有以下GraphQL查询(使用Apollo Client JS):

I have the following GraphQL query (using Apollo Client JS):

query GetUsers($searchFilter: String) {
    users(
        first: 10,
        filter: { search: $searchFilter }
    ) {
        nodes {
            id
            name
        }
    }
}

当我传入 $ searchFilter 参数时，此方法效果很好.但是，我希望此 $ searchFilter 参数为可选.因此，当它为 null 时，它不会应用该过滤器.

This works well when I pass in the $searchFilter argument. However, I want this $searchFilter argument to be optional. So when it's null it doesn't apply the filter.

这似乎很简单，但是API要求 search 不可为空.因此，不允许传入 filter:{搜索:null} .

This seems simple enough, but the API requires the search to be non-nullable. So passing in filter: { search: null } is not allowed.

我想实现以下目标:

query GetUsers($searchFilter: String) {
    users(
        first: 10,
        filter: $searchFilter = null ? null : { search: $searchFilter }
    ) {
        nodes {
            id
            name
        }
    }
}

如何有条件地包含 filter 参数?

How do I conditionally include the filter argument?

推荐答案

只需传递(整个早先组成/准备好"的)值作为 filter (在查询时定义)变量.将此变量保留为未定义状态即可.

Just pass (entire 'composed/prepared earlier') value for filter (define at query) variable. Leaving this variable undefined makes it optional.

query GetUsers($filter: SomeFilterInputType) {
  users(
    first: 10, 
    filter: $filter ) {

在[query]变量中为 filter 传递

值:

pass value for filter in [query] variables:

{
  filter: { search: 'sth'}
}

...，其中 SomeFilterInputType 是[ users query] arg类型名称，可以从graphiql/playground文档中提供的API规范中读取...或服务器代码/类型defs

... where SomeFilterInputType is a [users query] arg type name, it can be read from API specs, available in graphiql/playground docs ... or server code/type defs

可以使用QUERY VARIABLES在graphiql/playground中对其进行测试.

It can be tested in graphiql/playground using QUERY VARIABLES.

变量是具有相同结构的对象，可以有条件地轻松创建/修改.

variables passed from JavaScript is an object with the same structure, easily created/modified conditionally.

在这种情况下， SomeFilterInputType (类型名称后没有！标记)表示可以将其( filter 变量)设置为空/未定义-通常可选的args可以为空(不是必需的).如果API/BE规范中需要一些arg，则客户端中也必须使用它.

In this case SomeFilterInputType (no ! mark after type name) means it (filter variable) can be nulled/undefined - usually optional args are nullable (not required). If some arg is required in API/BE specs then it must be required in client, too.

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