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snippets/js/s/initialize-array-until.md

@@ -0,0 +1,37 @@
+---
+title: Initialize array until
+type: snippet
+language: javascript
+tags: [array]
+author: chalarangelo
+cover: neon-desk-2
+dateModified: 2023-06-22T05:00:00-04:00
+---
+
+Initializes and fills an array with values generated by a function, until a condition is met.
+
+- Create an empty array, `arr`, an index variable `i` and an element `el`.
+- Use a `do...while` loop to add elements to the array, using the `mapFn` function, until the `conditionFn` function returns `true` for the given index `i` and element `el`.
+- The condition function, `conditionFn`, takes three arguments: the current index, the previous element and the array itself.
+- The mapping function, `mapFn`, takes three arguments: the current index, the current element and the array itself.
+
+```js
+const initializeArrayUntil = (conditionFn, mapFn) => {
+  const arr = [];
+  let i = 0;
+  let el = undefined;
+  do {
+    el = mapFn(i, el, arr);
+    arr.push(el);
+    i++;
+  } while (!conditionFn(i, el, arr));
+  return arr;
+};
+```
+
+```js
+initializeArrayUntil(
+  (i, val) => val > 10,
+  (i, val, arr) => (i <= 1 ? 1 : val + arr[i - 2])
+); // [1, 1, 2, 3, 5, 8, 13]
+```

snippets/js/s/initialize-array-while.md

@@ -0,0 +1,37 @@
+---
+title: Initialize array while
+type: snippet
+language: javascript
+tags: [array]
+author: chalarangelo
+cover: neon-desk-1
+dateModified: 2023-06-20T05:00:00-04:00
+---
+
+Initializes and fills an array with values generated by a function, while a condition is met.
+
+- Create an empty array, `arr`, an index variable `i` and an element `el`.
+- Use a `while` loop to add elements to the array, using the `mapFn` function, as long as the `conditionFn` function returns `true` for the given index `i` and element `el`.
+- The condition function, `conditionFn`, takes three arguments: the current index, the previous element and the array itself.
+- The mapping function, `mapFn`, takes three arguments: the current index, the current element and the array itself.
+
+```js
+const initializeArrayWhile = (conditionFn, mapFn) => {
+  const arr = [];
+  let i = 0;
+  let el = mapFn(i, undefined, arr);
+  while (conditionFn(i, el, arr)) {
+    arr.push(el);
+    i++;
+    el = mapFn(i, el, arr);
+  }
+  return arr;
+};
+```
+
+```js
+initializeArrayWhile(
+  (i, val) => val < 10,
+  (i, val, arr) => (i <= 1 ? 1 : val + arr[i - 2])
+); // [1, 1, 2, 3, 5, 8]
+```

snippets/js/s/initialize-array-with-values.md

@@ -3,18 +3,19 @@ title: Initialize array with values
 type: snippet
 language: javascript
 tags: [array]
+author: chalarangelo
 cover: flower-portrait-1
 dateModified: 2020-10-20T23:02:01+03:00
 ---
 
 Initializes and fills an array with the specified values.
 
-- Use `Array.from()` to create an array of the desired length, `Array.prototype.fill()` to fill it with the desired values.
+- Use the `Array()` constructor to create an array of the desired length.
+- Use `Array.prototype.fill()` to fill it with the desired values.
 - Omit the last argument, `val`, to use a default value of `0`.
 
 ```js
-const initializeArrayWithValues = (n, val = 0) =>
-  Array.from({ length: n }).fill(val);
+const initializeArrayWithValues = (n, val = 0) => Array(n).fill(val);
 ```
 
 ```js

snippets/js/s/initialize-mapped-array.md

@@ -0,0 +1,27 @@
+---
+title: Initialize mapped array
+type: snippet
+language: javascript
+tags: [array]
+author: chalarangelo
+cover: yellow-shoes
+dateModified: 2023-06-13T05:00:00-04:00
+---
+
+Initializes and fills an array with the specified values, using a mapping function.
+
+- Use the `Array()` constructor to create an array of the desired length.
+- Use `Array.prototype.fill()` to fill it with `null` values.
+- Use `Array.prototype.map()` to fill it with the desired values, using the provided function, `mapFn`.
+- Omit the second argument, `mapFn`, to map each element to its index.
+
+```js
+const initializeMappedArray = (n, mapFn = (_, i) => i) =>
+  Array(n).fill(null).map(mapFn);
+```
+
+```js
+initializeMappedArray(5); // [0, 1, 2, 3, 4]
+initializeMappedArray(5, i => `item ${i + 1}`);
+// ['item 1', 'item 2', 'item 3', 'item 4', 'item 5']
+```