add remove, getSection

builder/ARRAY.ts

@@ -73,6 +73,28 @@ export class ARR<I> implements WritableBuilder<Array<I>, ARR<I>>, Logical {
     return this.value.entries();
   }
 
+  /**
+   * Attempts to remove an element in the array if found.
+   * @param element 
+   */
+  public remove(element: I): this {
+    const t = this.value.findIndex((x)=>x === element)
+    if(t != -1) this.value.splice(t, 1);
+    return this;
+  }
+
+  /**
+   * Modifies the array to be a section of itself.
+   * For both start and end, a negative index can be used to indicate an offset from the end of the array.
+   * For example, -2 refers to the second to last element of the array.
+   * @param start 
+   * @param end 
+   */
+  public getSection(start: number, end: number): this {
+    this.value = this.value.slice(start, end);
+    return this;
+  }
+
   /**
      * join the array together into a string
      * @param separator 

tests/ARRAY_test.ts

@@ -3,6 +3,8 @@ import {
   assertArrayIncludes,
   assertStringIncludes,
   fail,
+  assertEquals,
+  assertNotEquals
 } from "https://deno.land/std@0.90.0/testing/asserts.ts";
 import { ARRAY } from "../mod.ts";
 
@@ -125,3 +127,26 @@ Deno.test("Test array entries", () => {
   // merely runs the internal entries. no need for testing
   ARRAY(["hello"]).entries();
 });
+Deno.test("Test array remove", () => {
+  let called = false;
+  ARRAY(["hello", "world"]).remove("world").do((x)=>{
+    assertArrayIncludes(x, ["hello"]);
+    called = true;
+  });
+
+  ARRAY(["hello", "world"]).remove("x").do((x)=>{
+    assertArrayIncludes(x, ["hello", "world"]);
+    called = true;
+  });
+  if(!called) fail("clause was never called");
+});
+Deno.test("Test array getSection", () => {
+  let called = false;
+  ARRAY([1,2,3,4,5,6,7,8,9,10]).getSection(0,3).do((x)=>{
+    assertEquals(x.length, 3);
+    assertEquals(x[0], 1);
+    assertNotEquals(x, [1,2,3,4,5,6,7,8,9,10]);
+    called = true;
+  })
+  if(!called) fail("clause was never called");
+});