feat: add support for configuration files

.mementorc

@@ -0,0 +1,5 @@
+{
+  "targetUrl": "https://api.punkapi.com/v2",
+  "delay": 2,
+  "port": 3344
+}

README.md

@@ -9,7 +9,11 @@ This project was bootstrapped with [TSDX](https://github.com/jaredpalmer/tsdx).
 ## Getting started
 
 ```
-# Usage
+# Usage with configuration file
+# You may use any configuration file supported by https://github.com/davidtheclark/cosmiconfig (e.g. .mementorc, memento.config.js, ...)
+npx @antoinechalifour/memento
+
+# Usage with CLI  args
 npx @antoinechalifour/memento --targetUrl=<YOUR API BASE URL> --port=<THE PORT>
 
 # Example for caching Punk API
@@ -21,6 +25,18 @@ npx @antoinechalifour/memento --targetUrl=https://api.punkapi.com/v2 --delay=300
 
 ### Options
 
+#### Configuration file example
+You may use any configuration file supported by [cosmiconfig](https://github.com/davidtheclark/cosmiconfig). For instance, you may create a `.mementorc` in your project root :
+
+```
+{
+  "targetUrl": "https://api.punkapi.com/v2",
+  "delay": 2,
+  "port": 3344
+}
+```
+
+#### Command Line Options
 The following options can be used in the command line :
 
 | Option    | Description                                             | Example               | Default value |

package.json

@@ -42,6 +42,7 @@
   },
   "devDependencies": {
     "@types/axios": "^0.14.0",
+    "@types/cosmiconfig": "^5.0.3",
     "@types/jest": "^24.0.17",
     "@types/koa": "^2.0.49",
     "@types/koa-bodyparser": "^4.3.0",
@@ -67,6 +68,7 @@
     "awilix": "^4.2.2",
     "awilix-koa": "^4.0.0",
     "axios": "^0.19.0",
+    "cosmiconfig": "^5.2.1",
     "koa": "^2.7.0",
     "koa-bodyparser": "^4.2.1",
     "koa-logger": "^3.2.1",

src/index.ts

@@ -1,26 +1,61 @@
 import yargs from 'yargs';
 import assert from 'assert';
 import { createContainer, asClass, asValue } from 'awilix';
+import cosmiconfig from 'cosmiconfig';
 
 import { createApp } from './app';
 import { RespondToRequest } from './domain/usecase';
 import { ResponseRepositoryMemory } from './infrastructure/repository';
 import { NetworkServiceAxios } from './infrastructure/service';
 
-const cliArgs = yargs.argv;
+interface Configuration {
+  targetUrl: string;
+  delay: number;
+  port: number;
+}
 
-assert(cliArgs.targetUrl, 'targetUrl option is required');
+function getDelayFromString(str: string) {
+  return str ? parseInt(str, 10) : 0;
+}
 
-const targetUrl = cliArgs.targetUrl as string;
-const delay = cliArgs.delay ? parseInt(cliArgs.delay as string, 10) : 0;
-const port = cliArgs.port ? parseInt(cliArgs.port as string, 10) : 3344;
+function getPortFromString(port: string) {
+  return port ? parseInt(port, 10) : 3344;
+}
+
+function loadConfigurationFromFile(): Configuration | null {
+  const configExplorer = cosmiconfig('memento');
+  const cosmicConfiguration = configExplorer.searchSync();
+
+  if (!cosmicConfiguration) {
+    return null;
+  }
+
+  return {
+    targetUrl: cosmicConfiguration.config.targetUrl,
+    delay: getDelayFromString(cosmicConfiguration.config.delay),
+    port: getPortFromString(cosmicConfiguration.config.port),
+  };
+}
+
+function loadConfigurationFromCli(): Configuration {
+  const cliArgs = yargs.argv;
+  const targetUrl = cliArgs.targetUrl as string;
+  const delay = getDelayFromString(cliArgs.delay as string);
+  const port = getPortFromString(cliArgs.port as string);
+
+  return { targetUrl, delay, port };
+}
+
+const configuration = loadConfigurationFromFile() || loadConfigurationFromCli();
+
+assert(configuration.targetUrl, 'targetUrl option is required');
 
 const container = createContainer();
 
 container.register({
   // Constants
-  targetUrl: asValue(targetUrl),
-  delay: asValue(delay),
+  targetUrl: asValue(configuration.targetUrl),
+  delay: asValue(configuration.delay),
 
   // Use cases
   respondToRequestUseCase: asClass(RespondToRequest),
@@ -32,4 +67,4 @@ container.register({
   networkService: asClass(NetworkServiceAxios).singleton(),
 });
 
-createApp({ port, container }).run();
+createApp({ port: configuration.port, container }).run();

yarn.lock

@@ -909,6 +909,13 @@
     "@types/keygrip" "*"
     "@types/node" "*"
 
+"@types/cosmiconfig@^5.0.3":
+  version "5.0.3"
+  resolved "https://registry.yarnpkg.com/@types/cosmiconfig/-/cosmiconfig-5.0.3.tgz#880644bb155d4038d3b752159684b777b0a159dd"
+  integrity sha512-HgTGG7X5y9pLl3pixeo2XtDEFD8rq2EuH+S4mK6teCnAwWMucQl6v1D43hI4Uw1VJh6nu59lxLkqXHRl4uwThA==
+  dependencies:
+    "@types/node" "*"
+
 "@types/eslint-visitor-keys@^1.0.0":
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/@types/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#1ee30d79544ca84d68d4b3cdb0af4f205663dd2d"