feat: assoc, deepclone and pick

README.md

@@ -35,6 +35,7 @@ These are the functions under the `kudoJS.*` namespace
 * [`kudoJS.compose`](docs/helper-functions.md#kudojscompose)
 * [`kudoJS.constant`](docs/helper-functions.md#kudojsconstant)
 * [`kudoJS.fmap`](docs/helper-functions.md#kudojsfmap)
+* [`kudoJS.assoc`](docs/helper-functions.md#kudojsassoc)
 * [`kudoJS.bimap`](docs/helper-functions.md#kudojsbimap)
 * [`kudoJS.chain`](docs/helper-functions.md#kudojschain)
 * [`kudoJS.caseOf`](docs/helper-functions.md#kudojscaseof)
@@ -44,6 +45,7 @@ These are the functions under the `kudoJS.*` namespace
 * [`kudoJS.liftA4`](docs/helper-functions.md#kudojslifta4)
 * [`kudoJS.liftA5`](docs/helper-functions.md#kudojslifta5)
 * [`kudoJS.when`](docs/helper-functions.md#kudojswhen)
+* [`kudoJS.pick`](docs/helper-functions.md#kudojspick)
 * [`kudoJS.prop`](docs/helper-functions.md#kudojsprop)
 * [`kudoJS.eitherToMaybe`](docs/helper-functions.md#kudojseithertomaybe)
 * [`kudoJS.maybeToEither`](docs/helper-functions.md#kudojsmaybeToEither)

docs/helper-functions.md

@@ -9,6 +9,7 @@ These are the functions under the `kudoJS.*` namespace
 		- [`kudoJS.compose`](#kudojscompose)
 		- [`kudoJS.constant`](#kudojsconstant)
 		- [`kudoJS.fmap`](#kudojsfmap)
+		- [`kudoJS.assoc`](#kudojsassoc)
 		- [`kudoJS.bimap`](#kudojsbimap)
 		- [`kudoJS.chain`](#kudojschain)
 		- [`kudoJS.caseOf`](#kudojscaseof)
@@ -19,6 +20,7 @@ These are the functions under the `kudoJS.*` namespace
 		- [`kudoJS.liftA5`](#kudojslifta5)
 		- [`kudoJS.when`](#kudojswhen)
 		- [`kudoJS.prop`](#kudojsprop)
+		- [`kudoJS.pick`](#kudojspick)
 		- [`kudoJS.eitherToMaybe`](#kudojseithertomaybe)
 		- [`kudoJS.maybeToEither`](#kudojsmaybetoeither)
 
@@ -107,6 +109,22 @@ Takes a function and a functor, applies the function to each of the functor's va
 
 ----
 
+
+### `kudoJS.assoc`
+
+Associates a value to the specified key in the object. This returns a clone of the original object
+
+`assoc(key: string, value: A, o: {[k:string]: A}): {[k:string]: A}`
+
+
+| Param | Type | Description |
+| --- | --- | --- |
+| key | <code>string</code> | Key |
+| value | <code>function</code> | Value to be assigned to key in object |
+| o | <code>Object</code> | Object to which value needs to be assigned against the Key |
+
+----
+
 ### `kudoJS.bimap`
 
 Maps both sides of the disjunction
@@ -259,6 +277,19 @@ Returns a Maybe Just if value exists for the given key else returns a Nothing
 
 ----
 
+
+### `kudoJS.pick`
+Returns a Maybe Just containing the object with just the keys if values exists for the given keys else returns a Nothing
+
+`pick( keys: Array<string>, o: { [k: string]: A}): Maybe<{[k:string]: A}>`
+
+| Param | Type | Description |
+| --- | --- | --- |
+| keys | <code>Array<string></code> | Keys |
+| o | <code>Object</code> | Key Value Object |
+
+----
+
 ### `kudoJS.eitherToMaybe`
 Converts an Either type to a Maybe Type
 

src/adt/Maybe/index.ts

@@ -196,5 +196,15 @@ const _prop = <A>(
     if (!o) return Maybe.Nothing();
     return key in o ? Maybe.fromNullable(o[key]) : Maybe.Nothing();
 };
-
 export const prop = curry(_prop);
+
+function _pick(arr: Array<string>, o: any) {
+    if (!o || arr.length <= 0) return Maybe.Nothing();
+    const v = arr.reduce((acc: any, key) => {
+        if (o[key]) acc[key] = o[key];
+        return acc;
+    }, {});
+
+    return Object.keys(v).length > 0 ? Maybe.Just(v) : Maybe.Nothing();
+}
+export const pick = curry(_pick);

src/adt/Maybe/maybe.test.ts

@@ -4,7 +4,7 @@ import compose from "../../function/compose";
 import fmap from "../../function/fmap";
 import id from "../../function/id";
 import Either from "../Either";
-import Maybe, { eitherToMaybe, prop } from ".";
+import Maybe, { eitherToMaybe, prop, pick } from ".";
 
 // const laws: any = require("laws");
 // console.log(laws);
@@ -216,5 +216,23 @@ test("Maybe", t => {
         "prop returns a Nothing if value does not exists"
     );
 
+    t.equals(
+        Maybe.isNothing(pick(["d"], undefined)),
+        true,
+        "should return 'Nothing' if object is undefined"
+    );
+
+    t.equals(
+        Maybe.isNothing(pick(["d"], {})),
+        true,
+        "should return 'Nothing' if object is does not have key"
+    );
+
+    t.equals(
+        pick(["d"], { d: 1 }).getValue().d,
+        1,
+        "should return 'Just(value)' if object has key"
+    );
+
     t.end();
 });

src/function/assoc/assoc.test.ts

@@ -0,0 +1,15 @@
+import * as test from "tape";
+import assoc from "./";
+
+test("assoc", t => {
+    t.throws(
+        () => assoc("d", 1, undefined),
+        "should throw error if object is undefined"
+    );
+
+    t.equals(assoc("d", 1, {}).d, 1, "should set the value to a key in object");
+
+    const o = {};
+    t.notEquals(assoc("d", 1, o), o, "should not mutate original object");
+    t.end();
+});

src/function/assoc/index.ts

@@ -0,0 +1,11 @@
+import curry from "../curry";
+import objectDeepClone from "../deepClone";
+
+function assoc<A>(key: string, val: A, obj: any): any {
+    if (!obj || typeof obj !== "object")
+        throw new Error("assoc: expects an object");
+    const o = objectDeepClone(obj);
+    o[key] = val;
+    return o;
+}
+export default curry(assoc);

src/function/deepClone/deepClone.test.ts

@@ -0,0 +1,16 @@
+import * as test from "tape";
+import deepClone from "./";
+
+test("deep clone", t => {
+    t.equals(deepClone(1), 1, "should return value if type is not object");
+    const o1 = { d: 1 };
+    t.notEquals(deepClone(o1), o1, "should not mutate original object");
+    const s = { p: 1 };
+    const o2 = { d: s };
+    t.notEquals(
+        deepClone(o2).d,
+        o2.d,
+        "returned value should not be deep equal to original value"
+    );
+    t.end();
+});

src/function/deepClone/index.ts

@@ -0,0 +1,11 @@
+export default function objectDeepClone(o: any) {
+    if (o == null || typeof o !== "object") return o;
+    const clone: any = Array.isArray(o) ? [] : {};
+    Object.keys(o).map(k => {
+        if (o.hasOwnProperty(k)) {
+            clone[k] = objectDeepClone(o[k]);
+        }
+    });
+
+    return clone;
+}

src/index.ts

@@ -1,11 +1,12 @@
 /* istanbul ignore file */
 
 import Either, { maybeToEither } from "./adt/Either";
-import Maybe, { eitherToMaybe, prop } from "./adt/Maybe";
+import Maybe, { eitherToMaybe, pick, prop } from "./adt/Maybe";
 import Pair from "./adt/Pair";
 import Reader from "./adt/Reader";
 import State from "./adt/State";
 import Task from "./adt/Task";
+import assoc from "./function/assoc";
 import bimap from "./function/bimap";
 import caseOf from "./function/caseOf";
 import chain from "./function/chain";
@@ -27,6 +28,7 @@ export default {
     Reader,
     State,
     Task,
+    assoc,
     bimap,
     caseOf,
     chain,
@@ -42,5 +44,6 @@ export default {
     maybeToEither,
     ocurry,
     once,
+    pick,
     prop
 };