如何在GraphQL中检查具有正则表达式的数组

Question

I need to check the existence of some elements in an array as such

I have an array as such

ar = ['one','two','three']

I want to know how I can individually check the elements in the regular expression code below instead of "/something/" that would map through my array and check if they exist in graphQL one by one.

similar : allCockpitHello (filter: {Association : {value : {regex: "\/something/" }}} limit:2){
      nodes{
        Name{
          value
        }
}

Answer 1

GraphQL is not a magic bullet - it's only a query language, it 'transports' your needs to the engine (local client, remote server ...) where all the necessary processing takes place.

In this case you probably need to pass your array and expression as variables to the server (resolver). If processing is expensive results (similar relation) should be already defined, cached, preprocessed, etc.

If dataset is small you can do this entirely client-side - iterate over an array (fetched using graphql).

Answer 2

You need to have the regex string as an input parameter to be used by the resolver, GraphQL is not going to do the filter for you, you need to do/call that logic in the resolver based on your inputs.

Based on your example, you could have something like this on the schema and resolver:

type Node {
   name: String!
}

type NodeQueries {
   nodes (filterRegEx :String): [Node]!
}

Once you have the input string on the resolver, the implementation of the filter mechanism is up to you.

const resolvers = {
...
NodeQueries: {
    nodes: (parent, params) => {
      const {filterRegEx} = params; // regex input string

      const ar = ['one','two','three'];

      // Create a RegExp based on the input, 
      // Compare the with the elements in ar and store the result...
      // You might end up with ... res = ['one', 'three'];
      // Now map the result to match your schema:

      return _.map(res, name => ({name}) ); // to end up with [{name: 'one'}, {name: 'three'}]
    }
}
...

}