既存のAWSリソースを使用する

import { Amplify } from 'aws-amplify';
import { parseAmplifyConfig } from "aws-amplify/utils";
import outputs from '../amplify_outputs.json';

const amplifyConfig = parseAmplifyConfig(outputs);

// Add existing resource to the existing configuration.
Amplify.configure({
  ...amplifyConfig,
  API: {
    ...amplifyConfig.API,
    REST: {
      ...amplifyConfig.API?.REST,
      YourAPIName: {
        endpoint:
          'https://abcdefghij1234567890.execute-api.us-east-1.amazonaws.com/stageName',
        region: 'us-east-1' // Optional
      }
    }
  }
});