js-concepts: parallel programming with js

Author: baochau.dinh

Parallel/README.md

@@ -0,0 +1,4 @@
+- `Promise.race()` lets you know as soon as one of the given promises either fulfills or rejects
+- `Promise.allSettled()` lets you know when all promises either fulfill or reject
+- `Promise.all()` lets you know as soon as one of the given promises rejects or when all of them fulfill
+- `Promises.any()` lets you know as soon as one of the given promises fulfills or when none of them fulfills.

Parallel/iterators.js

@@ -0,0 +1,40 @@
+const collection = {
+  a: 10,
+  b: 20,
+  c: 30,
+  [Symbol.asyncIterator]() {
+    const keys = Object.keys(this);
+    console.log('keys: ', keys);
+    let i = 0;
+    return {
+      next: () => {
+        return new Promise((resolve, reject) => {
+          setTimeout(() => {
+            resolve({
+              value: this[keys[i++]],
+              done: i > keys.length
+            });
+          }, 1000);
+        });
+      }
+    };
+  }
+};
+
+const iterator = collection[Symbol.asyncIterator]();
+
+iterator.next().then(result => {
+  console.log('result: ', result);
+})
+
+iterator.next().then(result => {
+  console.log('result: ', result);
+})
+
+iterator.next().then(result => {
+  console.log('result: ', result);
+})
+
+iterator.next().then(result => {
+  console.log('result: ', result);
+})

Parallel/promises.js

@@ -0,0 +1,12 @@
+import fetch from 'node-fetch';
+
+const promise = fetch('https://eloux.com/async_js/examples/1.json');
+
+promise.then(result => {
+  // process;
+  const response = result.json();
+  return response;
+}).catch(err => {
+  console.error(err);
+});
+

package-lock.json

@@ -25,6 +25,7 @@
     "typescript": "^3.5.2"
   },
   "dependencies": {
-    "async": "^3.2.3"
+    "async": "^3.2.3",
+    "node-fetch": "^3.2.0"
   }
 }

package.json

@@ -728,6 +728,11 @@
   dependencies:
     "assert-plus" "^1.0.0"
 
+"data-uri-to-buffer@^4.0.0":
+  "integrity" "sha512-Vr3mLBA8qWmcuschSLAOogKgQ/Jwxulv3RNE4FXnYWRGujzrRWQI4m12fQqRkwX06C0KanhLr4hK+GydchZsaA=="
+  "resolved" "https://npm.vexere.net/data-uri-to-buffer/-/data-uri-to-buffer-4.0.0.tgz"
+  "version" "4.0.0"
+
 "data-urls@^1.0.0":
   "integrity" "sha512-YTWYI9se1P55u58gL5GkQHW4P6VJBJ5iBT+B5a7i2Tjadhv52paJG0qHX4A0OR6/t52odI64KP2YvFpkDOi3eQ=="
   "resolved" "https://npm.vexere.net/data-urls/-/data-urls-1.1.0.tgz"
@@ -1081,6 +1086,14 @@
   dependencies:
     "bser" "^2.0.0"
 
+"fetch-blob@^3.1.2", "fetch-blob@^3.1.4":
+  "integrity" "sha512-Eq5Xv5+VlSrYWEqKrusxY1C3Hm/hjeAsCGVG3ft7pZahlUAChpGZT/Ms1WmSLnEAisEXszjzu/s+ce6HZB2VHA=="
+  "resolved" "https://npm.vexere.net/fetch-blob/-/fetch-blob-3.1.4.tgz"
+  "version" "3.1.4"
+  dependencies:
+    "node-domexception" "^1.0.0"
+    "web-streams-polyfill" "^3.0.3"
+
 "filename-regex@^2.0.0":
   "integrity" "sha1-wcS5vuPglyXdsQa3XB4wH+LxiyY="
   "resolved" "https://npm.vexere.net/filename-regex/-/filename-regex-2.0.1.tgz"
@@ -1163,6 +1176,13 @@
     "combined-stream" "^1.0.6"
     "mime-types" "^2.1.12"
 
+"formdata-polyfill@^4.0.10":
+  "integrity" "sha512-buewHzMvYL29jdeQTVILecSaZKnt/RJWjoZCF5OW60Z67/GmSLBkOFM7qh1PI3zFNtJbaZL5eQu1vLfazOwj4g=="
+  "resolved" "https://npm.vexere.net/formdata-polyfill/-/formdata-polyfill-4.0.10.tgz"
+  "version" "4.0.10"
+  dependencies:
+    "fetch-blob" "^3.1.2"
+
 "fragment-cache@^0.2.1":
   "integrity" "sha1-QpD60n8T6Jvn8zeZxrxaCr//DRk="
   "resolved" "https://npm.vexere.net/fragment-cache/-/fragment-cache-0.2.1.tgz"
@@ -2519,6 +2539,20 @@
   "resolved" "https://npm.vexere.net/neo-async/-/neo-async-2.6.1.tgz"
   "version" "2.6.1"
 
+"node-domexception@^1.0.0":
+  "integrity" "sha512-/jKZoMpw0F8GRwl4/eLROPA3cfcXtLApP0QzLmUT/HuPCZWyB7IY9ZrMeKw2O/nFIqPQB3PVM9aYm0F312AXDQ=="
+  "resolved" "https://npm.vexere.net/node-domexception/-/node-domexception-1.0.0.tgz"
+  "version" "1.0.0"
+
+"node-fetch@^3.2.0":
+  "integrity" "sha512-8xeimMwMItMw8hRrOl3C9/xzU49HV/yE6ORew/l+dxWimO5A4Ra8ld2rerlJvc/O7et5Z1zrWsPX43v1QBjCxw=="
+  "resolved" "https://npm.vexere.net/node-fetch/-/node-fetch-3.2.0.tgz"
+  "version" "3.2.0"
+  dependencies:
+    "data-uri-to-buffer" "^4.0.0"
+    "fetch-blob" "^3.1.4"
+    "formdata-polyfill" "^4.0.10"
+
 "node-int64@^0.4.0":
   "integrity" "sha1-h6kGXNs1XTGC2PlM4RGIuCXGijs="
   "resolved" "https://npm.vexere.net/node-int64/-/node-int64-0.4.0.tgz"
@@ -3758,6 +3792,11 @@
     "exec-sh" "^0.2.0"
     "minimist" "^1.2.0"
 
+"web-streams-polyfill@^3.0.3":
+  "integrity" "sha512-EqPmREeOzttaLRm5HS7io98goBgZ7IVz79aDvqjD0kYXLtFZTc0T/U6wHTPKyIjb+MdN7DFIIX6hgdBEpWmfPA=="
+  "resolved" "https://npm.vexere.net/web-streams-polyfill/-/web-streams-polyfill-3.2.0.tgz"
+  "version" "3.2.0"
+
 "webidl-conversions@^4.0.2":
   "integrity" "sha512-YQ+BmxuTgd6UXZW3+ICGfyqRyHXVlD5GtQr5+qjiNW7bF0cqrzX500HVXPBOvgXb5YnzDd+h0zqyv61KUD7+Sg=="
   "resolved" "https://npm.vexere.net/webidl-conversions/-/webidl-conversions-4.0.2.tgz"