feat(resources): split up topics and languages

src/content/resources/language/javascript/promises/simplifying-promises.md

@@ -0,0 +1,72 @@
+---
+authors:
+  - "Xetera#0001"
+created_at: "2019/07/26"
+title: Simplifying Promises
+---
+
+The first naive attempt, using new Promise for something that already returns a promise.
+
+```js
+function doAsync(number) {
+  return new Promise(function (resolve, reject) {
+    doDatabase().then(function (dbResult) {
+      otherDbFunction(dbResult).then(function (secondResult) {
+        resolve(secondResult + 10);
+      });
+    });
+  });
+}
+```
+
+Turns out you don't need new Promise if you're working with a function that
+already returns a promise, you can just return the original thing.
+
+```js
+function doAsync(number) {
+  return doDatabase().then(function (dbResult) {
+    otherDbFunction(dbResult).then(function (secondResult) {
+      return secondResult + 10;
+    });
+  });
+}
+```
+
+You also don't have to nest `.then` functions, the whole point of promises
+is that they allow you to chain them sequentially.
+
+```js
+function doAsync(number) {
+  return doDatabase()
+    .then(function (dbResult) {
+      return otherDbFunction(dbResult);
+    })
+    .then(function (secondResult) {
+      return secondResult + 10;
+    });
+}
+```
+
+you also don't have to create a new function just to pass in one
+variable, you can pass in the entire function itself to the then block
+
+```js
+function doAsync(number) {
+  return doDatabase()
+    .then(otherDbFunction)
+    .then(function (secondResult) {
+      return secondResult + 10;
+    });
+}
+```
+
+And you don't need those returns if you just have ES6 arrow functions
+
+```js
+const doAsync = (number) =>
+  doDatabase()
+    .then(otherDbFunction)
+    .then((secondResult) => secondResult + 10);
+```
+
+Wow, that last one looks a lot cleaner to me than the first. Keeping that in mind, maybe we could be making some of our other functions cleaner as well