refactor: remove any type in isUndefined. (#207)

* fix: remove any type

* feat: add isDefined function

* feat: add throwIf function

* test: add isDefined test

* test: add throwIf test

* fix: format import path

* feat: add isNull function

* fix: isNull return type

* test: add new util function's type-check test case

* refactor: refactoring util function logic

* fix: rollback to original isEmpty logic

* fix: delete non-related code

src/index.ts

@@ -24,6 +24,7 @@ import isArray from "./isArray";
 import isBoolean from "./isBoolean";
 import isEmpty from "./isEmpty";
 import isNil from "./isNil";
+import isNull from "./isNull";
 import isNumber from "./isNumber";
 import isObject from "./isObject";
 import isString from "./isString";
@@ -92,6 +93,7 @@ export {
   isObject,
   isString,
   isUndefined,
+  isNull,
   join,
   juxt,
   last,

src/isNil.ts

@@ -1,3 +1,6 @@
+import isNull from "./isNull";
+import isUndefined from "./isUndefined";
+
 type Nullable<T> = T extends null | undefined ? T : never;
 
 /**
@@ -11,12 +14,6 @@ type Nullable<T> = T extends null | undefined ? T : never;
  * isNil(null); // true
  * ```
  */
-function isNil<T>(a: T): a is Nullable<T> {
-  if (a === undefined || a === null) {
-    return true;
-  }
-
-  return false;
-}
+const isNil = <T>(a: T): a is Nullable<T> => isUndefined(a) || isNull(a);
 
 export default isNil;

src/isNull.ts

@@ -0,0 +1,14 @@
+/**
+ * Checks if the given value is `null`.
+ *
+ * @example
+ * ```ts
+ * isNull(1); // false
+ * isNull('1'); // false
+ * isNull(undefined); // false
+ * isNull(null); // true
+ * ```
+ */
+const isNull = <T>(input: T | null): input is null => input === null;
+
+export default isNull;

src/isUndefined.ts

@@ -1,14 +1,12 @@
 /**
- * Returns true if `a` is a undefined.
+ * Checks if the given value is `undefined`.
  *
  * @example
  * ```ts
  * isUndefined(undefined); // true
  * isUndefined(2); // false
  * ```
  */
-function isUndefined(a: any): a is undefined {
-  return typeof a === "undefined";
-}
+const isUndefined = <T>(a: T | undefined): a is undefined => a === undefined;
 
 export default isUndefined;

test/apply.spec.ts

@@ -1,4 +1,4 @@
-import { apply, pipe, range, toArray } from "../src/index";
+import { apply, pipe, range, toArray } from "../src";
 
 describe("apply", function () {
   it("should apply given list to the function", function () {

test/consume.spec.ts

@@ -1,4 +1,4 @@
-import { consume, peek, pipe, toAsync } from "../src/index";
+import { consume, peek, pipe, toAsync } from "../src";
 
 describe("consume", function () {
   describe("sync", function () {

test/countBy.spec.ts

@@ -1,5 +1,5 @@
+import { countBy, filter, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { countBy, filter, pipe, toAsync } from "../src/index";
 
 type Obj = {
   category: "clothes" | "pants" | "shoes";

test/each.spec.ts

@@ -1,4 +1,4 @@
-import { each, map, pipe, range, toAsync } from "../src/index";
+import { each, map, pipe, range, toAsync } from "../src";
 
 describe("each", function () {
   describe("sync", function () {

test/every.spec.ts

@@ -1,5 +1,5 @@
+import { every, filter, map, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { every, filter, map, pipe, toAsync } from "../src/index";
 
 describe("every", function () {
   describe("sync", function () {

test/evolve.spec.ts

@@ -1,4 +1,4 @@
-import { evolve, pipe } from "../src/index";
+import { evolve, pipe } from "../src";
 
 describe("evolve", function () {
   const add1 = (a: number) => a + 1;

test/find.spec.ts

@@ -1,5 +1,5 @@
+import { filter, find, map, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { filter, find, map, pipe, toAsync } from "../src/index";
 import type Arrow from "../src/types/Arrow";
 
 describe("find", function () {

test/findIndex.spec.ts

@@ -1,5 +1,5 @@
+import { filter, findIndex, map, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { filter, findIndex, map, pipe, toAsync } from "../src/index";
 import type Arrow from "../src/types/Arrow";
 
 describe("findIndex", function () {

test/fromEntries.spec.ts

@@ -1,4 +1,4 @@
-import { fromEntries, toAsync } from "../src/index";
+import { fromEntries, toAsync } from "../src";
 
 //an object from string keyed-value pairs.
 describe("fromEntries", function () {

test/groupBy.spec.ts

@@ -1,5 +1,5 @@
+import { filter, groupBy, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { filter, groupBy, pipe, toAsync } from "../src/index";
 
 type Obj = {
   category: "clothes" | "pants" | "shoes";

test/gt.spec.ts

@@ -1,4 +1,4 @@
-import { filter, gt, pipe, toArray } from "../src/index";
+import { filter, gt, pipe, toArray } from "../src";
 
 describe("gt(greater then)", function () {
   describe("currying", function () {

test/gte.spec.ts

@@ -1,4 +1,4 @@
-import { filter, gte, pipe, toArray } from "../src/index";
+import { filter, gte, pipe, toArray } from "../src";
 
 describe("gte(greater then or equal to)", function () {
   describe("currying", function () {

test/head.spec.ts

@@ -1,5 +1,5 @@
+import { filter, head, map, pipe, toAsync } from "../src";
 import { range } from "../src/Lazy";
-import { filter, head, map, pipe, toAsync } from "../src/index";
 
 describe("head", function () {
   describe("sync", function () {

test/includes.spec.ts

@@ -1,4 +1,4 @@
-import { filter, includes, map, pipe, toAsync } from "../src/index";
+import { filter, includes, map, pipe, toAsync } from "../src";
 
 describe("includes", function () {
   describe("sync", function () {

test/indexBy.spec.ts

@@ -1,5 +1,5 @@
+import { filter, indexBy, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { filter, indexBy, pipe, toAsync } from "../src/index";
 
 type Obj = {
   category: "clothes" | "pants" | "shoes";

test/isArray.spec.ts

@@ -1,4 +1,4 @@
-import { isArray } from "../src/index";
+import { isArray } from "../src";
 
 describe("isArray", function () {
   it.each([undefined, null, true, 1, "a", Symbol("a"), () => null])(

test/isBoolean.spec.ts

@@ -1,4 +1,4 @@
-import { isBoolean } from "../src/index";
+import { isBoolean } from "../src";
 
 describe("isBoolean", function () {
   it.each([undefined, null, 1, "1", Symbol("a"), () => null])(

test/isEmpty.spec.ts

@@ -1,4 +1,4 @@
-import isEmpty from "../src/isEmpty";
+import { isEmpty } from "../src";
 
 describe("isEmpty", function () {
   const testParameters = [
@@ -22,8 +22,6 @@ describe("isEmpty", function () {
 
   it.each(testParameters)(
     "should Return `true` if the given value is empty value(%s)",
-    function (input, expected) {
-      expect(isEmpty(input)).toEqual(expected);
-    },
+    (input, expected) => expect(isEmpty(input)).toEqual(expected),
   );
 });

test/isNil.spec.ts

@@ -1,4 +1,4 @@
-import { isNil } from "../src/index";
+import { isNil } from "../src";
 
 describe("isNil", function () {
   it("should check if given value is `null` or `undefined`", function () {

test/isNull.spec.ts

@@ -0,0 +1,16 @@
+import { isNull } from "../src";
+
+describe("isNull", function () {
+  it.each([2, true, undefined, {}, [], Symbol("a"), "a"])(
+    "given non null then should be false",
+    function (a) {
+      const result = isNull(a);
+      expect(result).toEqual(false);
+    },
+  );
+
+  it("given null then should be true", function () {
+    const result = isNull(null);
+    expect(result).toEqual(true);
+  });
+});

test/isNumber.spec.ts

@@ -1,4 +1,4 @@
-import { isNumber } from "../src/index";
+import { isNumber } from "../src";
 
 describe("isNumber", function () {
   it.each([undefined, null, true, "1", Symbol("a"), () => null])(

test/isString.spec.ts

@@ -1,4 +1,4 @@
-import { isString } from "../src/index";
+import { isString } from "../src";
 
 describe("isString", function () {
   it.each([undefined, null, true, 1, Symbol("a"), () => null])(

test/isUndefined.spec.ts

@@ -1,4 +1,4 @@
-import isUndefined from "../src/isUndefined";
+import { isUndefined } from "../src";
 
 describe("isUndefined", function () {
   it.each([2, true, null, {}, [], Symbol("a"), "a"])(

test/join.spec.ts

@@ -1,5 +1,5 @@
+import { filter, join, map, pipe, toAsync } from "../src";
 import { asyncEmpty, empty } from "../src/_internal/utils";
-import { filter, join, map, pipe, toAsync } from "../src/index";
 
 describe("join", function () {
   describe("sync", function () {

test/last.spec.ts

@@ -1,4 +1,4 @@
-import { filter, last, map, pipe, range, toAsync } from "../src/index";
+import { filter, last, map, pipe, range, toAsync } from "../src";
 
 describe("last", function () {
   describe("sync", function () {

test/lt.spec.ts

@@ -1,4 +1,4 @@
-import { filter, lt, pipe, toArray } from "../src/index";
+import { filter, lt, pipe, toArray } from "../src";
 
 describe("lt(less then)", function () {
   describe("currying", function () {

test/lte.spec.ts

@@ -1,4 +1,4 @@
-import { filter, lte, pipe, toArray } from "../src/index";
+import { filter, lte, pipe, toArray } from "../src";
 
 describe("lte(less then or equal to)", function () {
   describe("currying", function () {

test/noop.spec.ts

@@ -1,4 +1,4 @@
-import { noop } from "../src/index";
+import { noop } from "../src";
 
 describe("noop", function () {
   it("should return `undefined`", function () {

test/nth.spec.ts

@@ -1,4 +1,4 @@
-import { filter, map, nth, pipe, toAsync } from "../src/index";
+import { filter, map, nth, pipe, toAsync } from "../src";
 
 describe("nth", function () {
   describe("sync", function () {

test/omit.spec.ts

@@ -1,4 +1,4 @@
-import { omit, pipe, toAsync } from "../src/index";
+import { omit, pipe, toAsync } from "../src";
 
 describe("omit", function () {
   describe("sync", function () {

test/omitBy.spec.ts

@@ -1,4 +1,4 @@
-import { omitBy, pipe } from "../src/index";
+import { omitBy, pipe } from "../src";
 
 describe("omitBy", function () {
   describe("sync", function () {

test/partition.spec.ts

@@ -1,5 +1,5 @@
+import { map, partition, pipe, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { map, partition, pipe, toAsync } from "../src/index";
 
 describe("partition", function () {
   describe("sync", function () {

test/pick.spec.ts

@@ -1,4 +1,4 @@
-import { pick, pipe, toAsync } from "../src/index";
+import { pick, pipe, toAsync } from "../src";
 
 describe("pick", function () {
   describe("sync", function () {

test/pickBy.spec.ts

@@ -1,4 +1,4 @@
-import { pickBy, pipe } from "../src/index";
+import { pickBy, pipe } from "../src";
 
 describe("pickBy", function () {
   describe("sync", function () {

test/pipe.spec.ts

@@ -8,7 +8,7 @@ import {
   reduce,
   toArray,
   toAsync,
-} from "../src/index";
+} from "../src";
 
 describe("pipe", function () {
   describe("sync", function () {

test/pipe1.spec.ts

@@ -1,4 +1,4 @@
-import { pipe1 } from "../src/index";
+import { pipe1 } from "../src";
 
 const add10 = (a: number) => a + 10;
 const add10Async = async (a: number) => a + 10;

test/prop.spec.ts

@@ -1,4 +1,4 @@
-import { pipe, prop } from "../src/index";
+import { pipe, prop } from "../src";
 
 describe("prop", () => {
   it("should return the value for the given object property", () => {

test/props.spec.ts

@@ -1,4 +1,4 @@
-import { pipe, props, toArray } from "../src/index";
+import { pipe, props, toArray } from "../src";
 
 describe("props", () => {
   const obj = { a: "v1", b: "v2", c: "v3", d: "v4", e: "v5", f: "v6" };

test/reduce.spec.ts

@@ -1,4 +1,4 @@
-import { filter, map, pipe, range, reduce, toAsync } from "../src/index";
+import { filter, map, pipe, range, reduce, toAsync } from "../src";
 
 const addNumber = (a: number, b: number) => a + b;
 const addNumberAsync = async (a: number, b: number) => a + b;

test/some.spec.ts

@@ -1,5 +1,5 @@
+import { filter, map, pipe, some, toAsync } from "../src";
 import { AsyncFunctionException } from "../src/_internal/error";
-import { filter, map, pipe, some, toAsync } from "../src/index";
 
 describe("some", function () {
   describe("sync", function () {

test/sort.spec.ts

@@ -1,4 +1,4 @@
-import { filter, pipe, sort, toAsync } from "../src/index";
+import { filter, pipe, sort, toAsync } from "../src";
 
 describe("sort", function () {
   const sortFn = (a: number | string, b: number | string) => {

test/sortBy.spec.ts

@@ -1,4 +1,4 @@
-import { filter, identity, pipe, sortBy, toAsync } from "../src/index";
+import { filter, identity, pipe, sortBy, toAsync } from "../src";
 
 describe("sortBy", function () {
   describe("sync", function () {

test/tap.spec.ts

@@ -1,4 +1,4 @@
-import { delay, map, pipe, range, tap, toArray, toAsync } from "../src/index";
+import { delay, map, pipe, range, tap, toArray, toAsync } from "../src";
 import { callFuncAfterTime } from "./utils";
 
 describe("tap", function () {

test/toArray.spec.ts

@@ -1,4 +1,4 @@
-import { range, toArray, toAsync } from "../src/index";
+import { range, toArray, toAsync } from "../src";
 
 const identityP = <T>(a: T) => Promise.resolve(a);
 

type-check/isNull.test.ts

@@ -0,0 +1,16 @@
+import { filter, isNull, pipe } from "../src";
+import * as Test from "../src/types/Test";
+
+const { checks, check } = Test;
+
+const res1 = isNull(undefined);
+const res2 = isNull(null);
+const res3 = isNull(3);
+const res4 = pipe([1, null, 2], filter(isNull));
+
+checks([
+  check<typeof res1, boolean, Test.Pass>(),
+  check<typeof res2, boolean, Test.Pass>(),
+  check<typeof res3, boolean, Test.Pass>(),
+  check<typeof res4, IterableIterator<null>, Test.Pass>(),
+]);