@enter-at/lambda-handlers/handler/BaseHandler.js

An opinionated Typescript package that facilitates specifying AWS Lambda handlers including input validation, error handling and response formatting.

"use strict";
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
    if (k2 === undefined) k2 = k;
    var desc = Object.getOwnPropertyDescriptor(m, k);
    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
      desc = { enumerable: true, get: function() { return m[k]; } };
    }
    Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
    if (k2 === undefined) k2 = k;
    o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
    Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
    o["default"] = v;
});
var __importStar = (this && this.__importStar) || function (mod) {
    if (mod && mod.__esModule) return mod;
    var result = {};
    if (mod != null) for (var k in mod) if (k !== "default" && Object.prototype.hasOwnProperty.call(mod, k)) __createBinding(result, mod, k);
    __setModuleDefault(result, mod);
    return result;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.BaseHandler = void 0;
const inputFormat = __importStar(require("../format/InputFormat"));
const outputFormat = __importStar(require("../format/OutputFormat"));
const index_1 = require("../index");
class BaseHandler {
    inputFormat;
    outputFormat;
    constructor(args) {
        this.inputFormat = args?.inputFormat ?? inputFormat.json;
        this.outputFormat = args?.outputFormat ?? outputFormat.json;
        if (args?.logger) {
            index_1.config.logger = args.logger;
        }
    }
    decorator(_target, _propertyName, propertyDescriptor) {
        propertyDescriptor.value = this.wrapper(propertyDescriptor.value);
        return propertyDescriptor;
    }
    wrapper(method) {
        const handler = this;
        return async function fn(event, context) {
            try {
                const instance = this;
                return handler.after(await method.apply(instance, handler.before(event, context)));
            }
            catch (err) {
                return handler.onException(err);
            }
        };
    }
    before(event, context) {
        return [this.formatInput(event), context];
    }
    after(output) {
        return this.formatOutput(output);
    }
    onException(exception) {
        throw exception;
    }
    formatInput(input) {
        return this.inputFormat.apply(input);
    }
    formatOutput(output) {
        return this.outputFormat.apply(output);
    }
}
exports.BaseHandler = BaseHandler;