previous N days from today as date string

snippets/daysAgo.md

@@ -0,0 +1,21 @@
+---
+title: daysAgo
+tags: date,intermediate
+---
+
+Returns previous N days from today as date string representation.
+
+- Use `new Date()` to get the current date, decrement using `Date.getDate()` and set the value to the result using `Date.setDate()`.
+- Use `Date.prototype.toISOString()` to return a string in `yyyy-mm-dd` format.
+
+```js
+const daysAgo = (n) => {
+  let t = new Date();
+  t.setDate(t.getDate() - Math.abs(n));
+  return t.toISOString().split('T')[0];
+};
+```
+
+```js
+daysAgo(20); // 2020-09-16 (if current date is 2020-10-06)
+```