@middy/http-partial-response/index.js

import mask from 'json-mask';
import { normalizeHttpResponse, jsonSafeParse } from '@middy/util';
const defaults = {
    filteringKeyName: 'fields'
};
const httpPartialResponseMiddleware = (opts = {})=>{
    const options = {
        ...defaults,
        ...opts
    };
    const { filteringKeyName } = options;
    const httpPartialResponseMiddlewareAfter = async (request)=>{
        const fields = request.event?.queryStringParameters?.[filteringKeyName];
        if (!fields) return;
        normalizeHttpResponse(request);
        const body = request.response.body;
        const bodyIsString = typeof body === 'string';
        const parsedBody = jsonSafeParse(body);
        if (typeof parsedBody !== 'object') return;
        const filteredBody = mask(parsedBody, fields);
        request.response.body = bodyIsString ? JSON.stringify(filteredBody) : filteredBody;
    };
    return {
        after: httpPartialResponseMiddlewareAfter
    };
};
export default httpPartialResponseMiddleware;