Add simple fetch API implementation

PR-URL: #88

Author: tshemsedinov

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## [Unreleased][unreleased]
 
 - Fixed Pool infinite loop case
+- Add simple `fetch` API implementation
 
 ## [3.5.14][] - 2021-09-21
 

README.md

@@ -16,8 +16,6 @@
 
 - `random(min: number, max?: number): number`
 - `sample(arr: Array<any>): any`
-- `ipToInt(ip?: string): number`
-- `parseHost(host?: string): string`
 - `parseParams(params: string): object`
 - `replace(str: string, substr: string, newstr: string): string`
 - `split(s: string, separator: string): [string, string]`
@@ -35,11 +33,17 @@
 - `namespaceByPath(namespace: object, path: string): object | null`
 - `makePrivate(instance: object): object`
 - `protect(allowMixins: Array<string>, ...namespaces: Array<object>): void`
-- `parseCookies(cookie: string): object`
 - `createAbortController(): AbortController`
 - `timeout(msec: number, signal?: EventEmitter): Promise<void>`
 - `delay(msec: number, signal?: EventEmitter): Promise<void>`
 
+## Network utilities
+
+- `ipToInt(ip?: string): number`
+- `parseHost(host?: string): string`
+- `parseCookies(cookie: string): object`
+- `fetch(url: string): Promise<string>`
+
 ## Crypto utilities
 
 - `cryptoRandom(): number`

lib/fetch.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const http = require('http');
+const https = require('https');
+
+const fetch = async (url) => {
+  const transport = url.startsWith('https') ? https : http;
+  return new Promise((resolve, reject) => {
+    transport.get(url, async (res) => {
+      const code = res.statusCode;
+      if (code !== 200) return reject(new Error(`HTTP status code ${code}`));
+      res.on('error', reject);
+      const chunks = [];
+      try {
+        for await (const chunk of res) chunks.push(chunk);
+        const json = Buffer.concat(chunks).toString();
+        const object = JSON.parse(json);
+        resolve(object);
+      } catch (error) {
+        return reject(error);
+      }
+    });
+  });
+};
+
+module.exports = { fetch };

metautil.d.ts

@@ -101,3 +101,5 @@ export class Pool {
   capture(): Promise<object | null>;
   release(item: object): void;
 }
+
+export function fetch(url: string): Promise<string>;

metautil.js

@@ -1,9 +1,10 @@
 'use strict';
 
-const utilities = require('./lib/utilities.js');
-const crypto = require('./lib/crypto.js');
-const async = require('./lib/async.js');
-const semaphore = require('./lib/semaphore.js');
-const pool = require('./lib/pool.js');
-
-module.exports = { ...utilities, ...crypto, ...semaphore, ...pool, ...async };
+module.exports = {
+  ...require('./lib/utilities.js'),
+  ...require('./lib/crypto.js'),
+  ...require('./lib/semaphore.js'),
+  ...require('./lib/pool.js'),
+  ...require('./lib/async.js'),
+  ...require('./lib/fetch.js'),
+};

test/fetch.js

@@ -0,0 +1,24 @@
+'use strict';
+
+const metatests = require('metatests');
+const metautil = require('..');
+
+const API_EXCHANGE = {
+  host: 'openexchangerates.org',
+  path: '/api/latest.json?app_id=',
+  key: '1f43ea96b1e343fe94333dd2b97a109d',
+};
+
+const getRate = async (currency) => {
+  const { host, path, key } = API_EXCHANGE;
+  const url = `https://${host}/${path}${key}`;
+  const data = await metautil.fetch(url);
+  const rate = data.rates[currency];
+  return rate;
+};
+
+metatests.test('Fetch', async (test) => {
+  const rate = await getRate('USD');
+  test.strictSame(rate, 1);
+  test.end();
+});