how to set headers to the http post request?

[wilmerxu]

use codegen from @graphql-codegen/core,how can i set headers to the graphql http post request?

const config = {
    documents: document
      ? [
          {
            location: outputFilePath,
            document: parse(document),
          },
        ]
      : Array[''],
    config: {
      withHooks: true,
    },
    filename: outputFilePath,
    schema: parse(printSchema(schema)),
    plugins: [{ typescript: {} }, { typescriptOperations: {} }, { typescriptReactApollo: {} }],
    pluginMap: {
      typescript,
      typescriptOperations,
      typescriptReactApollo,
    },
  };

  let output = await codegen(config);

[dotansimha]

You are passing the schema as GraphQLSchema object when using the programmatic usage. I'm not sure I understand what headers you refer to.
If you refer to the request's header, please check Apollo's documentation, it should be done using ApolloLink and the instance of ApolloClient, and has nothing to do with codegen.