Merge pull request #7 from Nisarg03/main

Update index.js

Author: Hetarth02

index.js

@@ -1,28 +1,34 @@
+// To throw error in case of invalid datatype.
 function _throw() {
     throw new TypeError("Must be a valid array!");
 }
 
+// To check if arr is array.
 function is_array(arr) {
     return Array.isArray(arr) ? true : _throw();
 }
 
+// To get the head or first element of the array.
 function head(arr) {
     is_array(arr);
     return arr[0];
 }
 
+// To get the tail last element of the array.
 function tail(arr) {
     is_array(arr);
     let element = arr.pop();
     arr.push(element);
     return element;
 }
 
+// To check the existence of an element inside the array.
 function in_array(arr, value) {
     is_array(arr);
     return arr.includes(value);
 }
 
+// To split arrays into fixed size chunks.
 function array_chunk(arr, chunk_size) {
     is_array(arr);
     if (typeof chunk_size != "number") {
@@ -44,6 +50,7 @@ function array_chunk(arr, chunk_size) {
     }
 }
 
+// To filter out arrays based on datatypes.
 function array_filter(arr) {
     is_array(arr);
     arr = arr.filter((e) => {
@@ -52,6 +59,7 @@ function array_filter(arr) {
     return arr;
 }
 
+// To get the frequency of occurence of each unique element inside the array.
 function array_frequency(arr) {
     is_array(arr);
     let freq_obj = {};
@@ -65,13 +73,24 @@ function array_frequency(arr) {
     return freq_obj;
 }
 
+// To convert Objects into Arrays.
 function object_to_array(obj) {
     let temp = [];
     const entries = Object.entries(obj);
     entries.forEach((ent) => temp.push(ent[1]));
     return temp;
 }
 
+// To get indexes of all occurences of an element inside an array.
+function get_all_indexes(arr, val) {
+    is_array(arr);
+    var indexes = [];
+    for(let i = 0; i < arr.length; i++)
+        if (arr[i] === val)
+            indexes.push(i);
+    return indexes;
+}
+
 export {
     head,
     tail,
@@ -81,4 +100,5 @@ export {
     array_filter,
     array_frequency,
     object_to_array,
+    get_all_indexes,
 };