map(), filter() & reduce() method implement

Author: in-imitable

Chapter 5/20_map_filter_reduce.js

@@ -0,0 +1,22 @@
+let arr = [45, 23, 21]
+// Array map method
+let a = arr.map((value, index, array) => {
+  // console.log(value, index, array)
+  return value + index
+})
+// console.log(arr)
+
+// Array filter method
+let arr2 = [45, 23, 21, 0, 3, 5]
+let a2 = arr2.filter((a) => {
+  return a < 10
+})
+// console.log(a2, arr2)
+
+// Array reduce method
+let arr3 = [1, 2, 3, 5, 2, 1]
+const reduce_func = (h1, h2) => {
+  return h1 + h2
+}
+let newarr3 = arr3.reduce(reduce_func)
+console.log(newarr3)