add map to ARRAY carpenter

Author: duart38

builder/ARRAY.ts

@@ -2,6 +2,8 @@ import { STR, STRING } from "../mod.ts";
 import { WritableBuilder } from "../types/Builder.ts";
 import { LOGICAL } from "../types/Logical.ts";
 import LogicalStack from "../types/LogicalStack.ts";
+type predicate<K> = ((val: K, index?: number, arr?:K[])=>boolean);
+type callBck<K> = ((val: K, index?: number, arr?:K[])=>K | any);
 
 export class ARR<I> extends LogicalStack<ARR<I>>
   implements WritableBuilder<Array<I>, ARR<I>>, ArrayLike<I> {
@@ -55,11 +57,30 @@ export class ARR<I> extends LogicalStack<ARR<I>>
    * @param predicate 
    * @returns 
    */
-     public thenFilter(predicate: (val: I, index?: number, arr?:I[])=>boolean): this {
+    public thenFilter(predicate: predicate<I>): this {
        if(this.lastStackMatched) this.filter(predicate);
       return this;
     }
 
+    /**
+     * Performs Map on the inner value regardless of conditions of previous calls.
+     * @param predicate 
+     * @returns 
+     */
+    public map(predicate: callBck<I>): this {
+      this.value = this.value.map(predicate);
+      return this;
+    }
+    /**
+     * Performs map only if the previous calls result in a true value.
+     * @param predicate 
+     * @returns 
+     */
+    public thenMap(predicate: callBck<I>): this {
+      if(this.lastStackMatched) this.map(predicate);
+      return this;
+    }
+
   /**
      * Checks if the current array length is of size 'n'
      * @param n 

tests/ARRAY_test.ts

@@ -174,3 +174,37 @@ Deno.test("Test array getSection", () => {
   });
   if (!called) fail("clause was never called");
 });
+
+Deno.test("Test array map", () => {
+  let called = false;
+  ARRAY([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]).map((x, i, a)=>{
+    return x * 10;
+  }).do((arr)=>{
+    assertEquals(arr[0], 10);
+    called = true;
+  })
+  if (!called) fail("clause was never called");
+});
+
+Deno.test("Test array thenMap true", () => {
+  let called = false;
+  ARRAY([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]).thenMap((x, i, a)=>{
+    return x * 10;
+  }).do((arr)=>{
+    assertEquals(arr[0], 10);
+    called = true;
+  })
+  if (!called) fail("clause was never called");
+});
+Deno.test("Test array thenMap false", () => {
+  let called = false;
+  ARRAY([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
+  .isOfSize(1)
+  .thenMap((x)=>{
+    return x * 10;
+  }).else((arr)=>{
+    assertEquals(arr[0], 1);
+    called = true;
+  })
+  if (!called) fail("clause was never called");
+});