feat: adds mapfilter

docs/src/routes/docs/datatypes/Array.svelte

@@ -1,6 +1,6 @@
 <script>
   import DocItemTitle from "$lib/DocItemTitle.svelte";
-  import DocTitle from '$lib/DocTitle.svelte';
+  import DocTitle from "$lib/DocTitle.svelte";
   import PageTitle from "$lib/PageTitle.svelte";
   import PrismJs from "$lib/PrismJS.svelte";
   import SinceVersion from "$lib/SinceVersion.svelte";
@@ -203,7 +203,9 @@ console.log(Array.get(2)(['a'])) // Error('Index 2 is out of bounds for length 1
 <article>
   <DocItemTitle title="get" />
   <p>
-    Fills an array <code>b</code> with <code>a</code> from index <code>start</code> to <code>end</code>.
+    Fills an array <code>b</code> with <code>a</code> from index
+    <code>start</code>
+    to <code>end</code>.
   </p>
   <SinceVersion>3.3.0</SinceVersion>
   <PrismJs
@@ -297,7 +299,8 @@ console.log(firstor([])) // 'not found'
 <article>
   <DocItemTitle title="filtermap" />
   <p>
-    Maps an array <code>a</code> by removing all elements that do not satisfy the predicate <code>p</code>.
+    Maps an array <code>a</code> by removing all elements that do not satisfy
+    the predicate <code>p</code>.
   </p>
   <SinceVersion>3.0.0</SinceVersion>
   <PrismJs
@@ -366,7 +369,8 @@ console.log(Array.fromfunctions([Num.add(1), Str.upper])([1, 'a'])) // ['2', 'A'
 <article>
   <DocItemTitle title="includes" />
   <p>
-    Determines whether an array includes a certain element, returning true or false as appropriate.
+    Determines whether an array includes a certain element, returning true or
+    false as appropriate.
   </p>
   <SinceVersion>3.2.0</SinceVersion>
   <PrismJs
@@ -458,9 +462,7 @@ console.log(Array.join('-')(['a', 'b', 'c'])) // 'a-b-c'
 
 <article>
   <DocItemTitle title="join" />
-  <p>
-    Creates a new array of a given size.
-  </p>
+  <p>Creates a new array of a given size.</p>
   <SinceVersion>3.2.0</SinceVersion>
   <PrismJs
     code={`
@@ -491,6 +493,21 @@ console.log(Array.map(String.uconcat('!'))(['a', 'b', 'c'])) // ['a!', 'b!', 'c!
   />
 </article>
 
+<article>
+  <DocItemTitle title="mapfilter" />
+  <SinceVersion>3.6.0</SinceVersion>
+  <PrismJs
+    code={`
+import { Array, Number } 'tiinvo';
+
+const fm = Array.filtermap(Number.umul(2), Number.gt(3));
+
+fm([1, 2, 3]) // [4, 6]
+`}
+    language="ts"
+  />
+</article>
+
 <article>
   <DocItemTitle title="none" />
   <p>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "tiinvo",
-  "version": "3.5.4",
+  "version": "3.6.0",
   "author": "Paolo Roth <octod>",
   "license": "MIT",
   "description": "A lib of types and utilities for your TypeScript and JavaScript projects",

src/__tests__/array.test.ts

@@ -140,6 +140,12 @@ describe(`array`, () => {
     expect(expect.arrayContaining(a.map(inc)([1, 2, 3]))).toEqual([2, 3, 4]);
   });
 
+  test(a.mapfilter.name, () => {
+    const fm = a.mapfilter(n.umul(2), n.gt(3));
+
+    expect(expect.arrayContaining(fm([1, 2, 3]))).toEqual([4, 6]);
+  })
+
   test(a.none.name, () => {
     const p = n.isEven;
 

src/array.ts

@@ -274,6 +274,7 @@ export const first = <a>(a: a[]) => a[0] as option<a>
 export const firstOr = <a>(a: a) => (b: a[]) => b[0] ?? a;
 /**
  * Maps an array `a` by removing all elements that do not satisfy the predicate `p`.
+ * The filter occurs before mapping the elements.
  * 
  * ```typescript
  * import { Array, Number } 'tiinvo';
@@ -466,6 +467,37 @@ export const make = <a = undefined>(size = 0, dv = undefined as unknown as a): a
  * @since 3.0.0
  */
 export const map = <a, b>(f: f.map<a, b>) => (a: a[]) => a.map(f);
+/**
+ * Maps an array `a` by removing all elements that do not satisfy the predicate `p`.
+ * The filter occurs after mapping the elements.
+ * 
+ * ```typescript
+ * import { Array, Number } 'tiinvo';
+ * 
+ * const fm = Array.filtermap(Number.umul(2), Number.gt(3));
+ * 
+ * fm([1, 2, 3]) // [4, 6]
+ * ```
+ * 
+ * @param f 
+ * @param p 
+ * @returns 
+ * @since 3.6.0
+ */
+export const mapfilter = <a, b>(f: f.map<a, b>, p: f.predicateE<b>) => (a: a[]) => {
+  const r = [] as b[];
+
+  for (let i = 0; i < a.length; i++) {
+    const v = a[i];
+    const m = f(v);
+
+    if (p(m)) {
+      r.push(m);
+    }
+  }
+
+  return r;
+}
 /**
  * Returns true if all elements of `a` do not meet the condition specified in the predicate `p`.
  *