From 5adaf7ba4ec9cb77b2afa0ad33c41d659ea93666 Mon Sep 17 00:00:00 2001
From: Chalarangelo <chalarangelo@gmail.com>
Date: Thu, 20 Jan 2022 19:31:40 +0200
Subject: [PATCH] Add 2 new generator snippets

---
 snippets/generateUntil.md | 28 ++++++++++++++++++++++++++++
 snippets/generateWhile.md | 28 ++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 snippets/generateUntil.md
 create mode 100644 snippets/generateWhile.md

diff --git a/snippets/generateUntil.md b/snippets/generateUntil.md
new file mode 100644
index 000000000..39ce4870a
--- /dev/null
+++ b/snippets/generateUntil.md
@@ -0,0 +1,28 @@
+---
+title: generateUntil
+tags: function,generator,advanced
+firstSeen: 2022-01-21T05:00:00-04:00
+---
+
+Creates a generator, that keeps producing new values until the given condition is met.
+
+- Initialize the current `val` using the `seed` value.
+- Use a `while` loop to iterate while the `condition` function called with the current `val` returns `false`.
+- Use `yield` to return the current `val` and optionally receive a new seed value, `nextSeed`.
+- Use the `next` function to calculate the next value from the current `val` and the `nextSeed`.
+
+```js
+const generateUntil = function* (seed, condition, next) {
+  let val = seed;
+  let nextSeed = null;
+  while (!condition(val)) {
+    nextSeed = yield val;
+    val = next(val, nextSeed);
+  }
+  return val;
+};
+```
+
+```js
+[...generateUntil(1, v => v > 5, v => ++v)]; // [1, 2, 3, 4, 5]
+```
diff --git a/snippets/generateWhile.md b/snippets/generateWhile.md
new file mode 100644
index 000000000..123183362
--- /dev/null
+++ b/snippets/generateWhile.md
@@ -0,0 +1,28 @@
+---
+title: generateWhile
+tags: function,generator,advanced
+firstSeen: 2022-01-21T05:00:00-04:00
+---
+
+Creates a generator, that keeps producing new values as long as the given condition is met.
+
+- Initialize the current `val` using the `seed` value.
+- Use a `while` loop to iterate while the `condition` function called with the current `val` returns `true`.
+- Use `yield` to return the current `val` and optionally receive a new seed value, `nextSeed`.
+- Use the `next` function to calculate the next value from the current `val` and the `nextSeed`.
+
+```js
+const generateWhile = function* (seed, condition, next) {
+  let val = seed;
+  let nextSeed = null;
+  while (condition(val)) {
+    nextSeed = yield val;
+    val = next(val, nextSeed);
+  }
+  return val;
+};
+```
+
+```js
+[...generateWhile(1, v => v <= 5, v => ++v)]; // [1, 2, 3, 4, 5]
+```