Merge branch 'master' into add-pullAtIndex

snippets/bottomVisible.md

@@ -6,6 +6,6 @@ Use `scrollY`, `scrollHeight` and `clientHeight` to determine if the bottom of t
 
 ```js
 const bottomVisible = () =>
-  document.documentElement.clientHeight + window.scrollY >= document.documentElement.scrollHeight || document.documentElement.clientHeight;
+  document.documentElement.clientHeight + window.scrollY >= (document.documentElement.scrollHeight || document.documentElement.clientHeight);
 // bottomVisible() -> true
 ```

snippets/countVowels.md

@@ -0,0 +1,11 @@
+### countVowels
+
+Retuns `number` of vowels in provided string.
+
+Use a regular expression to count number of vowels `(A, E, I, O, U)` in a `string`.
+
+```js
+const countVowels = str => (str.match(/[aeiou]/ig) || []).length;
+// countVowels('foobar') -> 3
+// countVowels('gym') -> 0
+```

snippets/differenceWith.md

@@ -0,0 +1,10 @@
+### differenceWith
+
+Filters out all values from an array for which the comparator function does not return `true`.
+
+Use `Array.filter()` and `Array.find()` to find the appropriate values.
+
+```js
+const differenceWith = (arr, val, comp) => arr.filter(a => !val.find(b => comp(a, b)))
+// differenceWith([1, 1.2, 1.5, 3], [1.9, 3], (a,b) => Math.round(a) == Math.round(b)) -> [1, 1.2]
+```

snippets/dropElements.md

@@ -2,12 +2,12 @@
 
 Removes elements in an array until the passed function returns `true`. Returns the remaining elements in the array.
 
-Loop through the array, using `Array.shift()` to drop the first element of the array until the returned value from the function is `true`.
+Loop through the array, using `Array.slice()` to drop the first element of the array until the returned value from the function is `true`.
 Returns the remaining elements.
 
 ```js
 const dropElements = (arr, func) => {
-  while (arr.length > 0 && !func(arr[0])) arr.shift();
+  while (arr.length > 0 && !func(arr[0])) arr = arr.slice(1);
   return arr;
 };
 // dropElements([1, 2, 3, 4], n => n >= 3) -> [3,4]

snippets/dropRight.md

@@ -0,0 +1,12 @@
+### dropRight
+
+Returns a new array with `n` elements removed from the right
+
+Check if `n` is shorter than the given array and use `Array.slice()` to slice it accordingly or return an empty array.
+
+```js
+const dropRight = (arr, n = 1) => n < arr.length ? arr.slice(0, arr.length - n) : []
+//dropRight([1,2,3]) -> [1,2]
+//dropRight([1,2,3], 2) -> [1]
+//dropRight([1,2,3], 42) -> []
+```

snippets/initializeArrayWithRange.md

@@ -1,12 +1,13 @@
 ### initializeArrayWithRange
 
-Initializes an array containing the numbers in the specified range.
+Initializes an array containing the numbers in the specified range where `start` and `end` are inclusive.
 
-Use `Array(end-start)` to create an array of the desired length, `Array.map()` to fill with the desired values in a range.
+Use `Array((end + 1) - start)` to create an array of the desired length, `Array.map()` to fill with the desired values in a range.
 You can omit `start` to use a default value of `0`.
 
 ```js
-const initializeArrayWithRange = (end, start = 0) =>
-  Array.from({ length: end - start }).map((v, i) => i + start);
-// initializeArrayWithRange(5) -> [0,1,2,3,4]
+const initializeArrayWithRange = (end, start = 0) => 
+  Array.from({ length: (end + 1) - start }).map((v, i) => i + start);
+// initializeArrayWithRange(5) -> [0,1,2,3,4,5]
+// initializeArrayWithRange(7, 3) -> [3,4,5,6,7]
 ```

snippets/median.md

@@ -7,7 +7,7 @@ Return the number at the midpoint if `length` is odd, otherwise the average of t
 
 ```js
 const median = arr => {
-  const mid = Math.floor(arr.length / 2), nums = arr.sort((a, b) => a - b);
+  const mid = Math.floor(arr.length / 2), nums = [...arr].sort((a, b) => a - b);
   return arr.length % 2 !== 0 ? nums[mid] : (nums[mid - 1] + nums[mid]) / 2;
 };
 // median([5,6,50,1,-5]) -> 5

snippets/pull.md

@@ -5,6 +5,8 @@ Mutates the original array to filter out the values specified.
 Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed.
 Use `Array.length = 0` to mutate the passed in array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values.
 
+_(For a snippet that does not mutate the original array see [`without`](#without))_
+
 ```js
 const pull = (arr, ...args) => {
   let pulled = arr.filter((v, i) => !args.includes(v));

snippets/pullAll.md

@@ -0,0 +1,16 @@
+### pullAll
+
+Mutates the original array to filter out the values specified (accepts an array of values).
+
+Use `Array.filter()` and `Array.includes()` to pull out the values that are not needed.
+Use `Array.length = 0` to mutate the passed in array by resetting it's length to zero and `Array.push()` to re-populate it with only the pulled values.
+
+```js
+const pullAll = (arr, pullArr) => {
+  let pulled = arr.filter((v, i) => !pullArr.includes(v));
+  arr.length = 0; pulled.forEach(v => arr.push(v));
+}
+// let myArray = ['a', 'b', 'c', 'a', 'b', 'c'];
+// pullAll(myArray, ['a', 'c']);
+// console.log(myArray) -> [ 'b', 'b' ]
+```

snippets/reverseString.md

@@ -2,10 +2,10 @@
 
 Reverses a string.
 
-Use array destructuring and `Array.reverse()` to reverse the order of the characters in the string.
+Use `split('')` and `Array.reverse()` to reverse the order of the characters in the string.
 Combine characters to get a string using `join('')`.
 
 ```js
-const reverseString = str => [...str].reverse().join('');
+const reverseString = str => str.split('').reverse().join('');
 // reverseString('foobar') -> 'raboof'
 ```

snippets/select.md

@@ -0,0 +1,13 @@
+### select
+
+Retrieve a property that indicated by the selector from object.
+
+If property not exists returns `undefined`.
+
+```js
+const select = (from, selector) =>
+  selector.split('.').reduce((prev, cur) => prev && prev[cur], from);
+
+// const obj = {selector: {to: {val: 'val to select'}}};
+// select(obj, 'selector.to.val'); -> 'val to select'
+```

snippets/without.md

@@ -4,6 +4,8 @@ Filters out the elements of an array, that have one of the specified values.
 
 Use `Array.filter()` to create an array excluding(using `!Array.includes()`) all given values.
 
+_(For a snippet that mutates the original array see [`pull`](#pull))_
+
 ```js
 const without = (arr, ...args) => arr.filter(v => !args.includes(v));
 // without([2, 1, 2, 3], 1, 2) -> [3]