Extend typings and tests

array/README.md

@@ -1,11 +1,11 @@
 # any
 
-Checks if the given array is not empty (contains at least one element).
+Checks if the given array is present and it is not empty (contains at least one element).
 
 ## Type signature
 
 ```
-(xs: any[]) => boolean
+(xs?: any[]) => boolean
 ```
 
 ## Examples
@@ -39,78 +39,146 @@ Checks if given arguments are all `Arrays`.
 
 # differs
 
+Checks if two arrays are not equal.
+
 # duplicates
 
+Lists all the duplicated values in the given array.
+
 # empty
 
+Empty array.
+
 # exact
 
+Takes exactly the given count of elements.
+
 # except
 
+Filters out the given value.
+
 # filterInPlace
 
+Filters the given array with the given predicate just like Array.filter but does it in-place thus mutates the original array.
+
 # find
 
+Finds an element by a predicate function within given array, otherwise returns the given fallback value or undefined when fallback is not present.
+
 # first
 
+Returns the first element or undefined when there are no elements in the given array.
+
 # flatMap
 
+Maps and flattens the result.
+
 # flatten
 
+Flattens the nested arrays by a single level.
+
 # intersection
 
+Finds common items between both arrays.
+
 # is
 
 # last
 
+Returns the last element or undefined when there are no elements in the given array.
+
 # lengthDiffers
 
+Checks if lengths of given arrays differ.
+
 # map
 
+Maps the given array with the given functions.
+
 # midpoint
 
+Returns the middle element or the right one when the number of elements is even.
+
 # minMax
 
+Computes minimum and maximum of the given array in a single run.
+
 # multiple
 
+Checks if the given array contains more than one element.
+
 # none
 
+Checks if the given array is empty.
+
 # partition
 
+Partitions the given array to the ones that pass the given predicate function and the ones that do not. By [convention of the Haskell's Data.Either](http://hackage.haskell.org/package/base-4.12.0.0/docs/Data-Either.html), values that pass the predicate are placed at right.
+
 # range
 
+Generates an array of numbers from 0 to n - 1.
+
 # repeat
 
+Repeats the given element by given count of times.
+
 # reverse
 
+Reverses the given array without mutating it (in contrast to Array.reverse).
+
 # reverseIf
 
-# rotate
+Reverses the given array when enabled.
 
 # second
 
+Returns the second element or undefined when there are less than two elements in the given array.
+
 # secondToLast
 
+Returns the second to last element or undefined when there are less than two elements in the given array.
+
 # shift
 
+Shifts the given array to the left and circulates the elements back by modulo of the array's length.
+
 # shuffle
 
+Shuffles the given array in random order with Math.random as the default.
+
 # shuffleInPlace
 
+Shuffles the given array in-place in random order with Math.random as the default.
+
 # single
 
+Checks if the given array contains exactly one element.
+
 # skip
 
+Skips the given count of elements from the given array.
+
 # sort
 
+Sorts the given array without mutating it.
+
 # sum
 
+Sums the given array of numbers.
+
 # take
 
-# transpose
+Takes up to given count of elements.
 
 # unique
 
+Returns only unique elements of the given array.
+
 # zip
 
+Zips given arrays together into pairs.
+
 # zipWith
+
+Zips given arrays together with the given function.

array/any.json

@@ -1,7 +1,7 @@
 {
   "name": "any",
-  "description": "Checks if the given array is not empty (contains at least one element).",
-  "signature": "(xs: any[]) => boolean",
+  "description": "Checks if the given array is present and it is not empty (contains at least one element).",
+  "signature": "(xs?: any[]) => boolean",
   "examples": [
     {
       "language": "javascript",

array/any.md

@@ -1,11 +1,11 @@
 # any
 
-Checks if the given array is not empty (contains at least one element).
+Checks if the given array is present and it is not empty (contains at least one element).
 
 ## Type signature
 
 ```
-(xs: any[]) => boolean
+(xs?: any[]) => boolean
 ```
 
 ## Examples

array/any.test.ts

@@ -11,7 +11,8 @@ describe("any", () => {
     expect(any([])).toBe(false);
   });
 
-  it("returns false if the given argument is falsy", () => {
+  it("returns false if the given array is missing or the argument is falsy", () => {
+    expect(any()).toBe(false);
     expect(any(null)).toBe(false);
     expect(any(undefined)).toBe(false);
   });

array/any.ts

@@ -1 +1 @@
-export default (xs: any[]): boolean => (xs ? xs.length > 0 : false);
+export default (xs?: any[]): boolean => (xs ? xs.length > 0 : false);

array/difference.test.ts

@@ -3,7 +3,7 @@
 import difference from "./difference.ts";
 
 describe("difference", () => {
-  it.skip("TODO", () => {
-    expect(difference()).toBeDefined();
+  it("skips all the elements present in the second array and keeps the rest", () => {
+    expect(difference([1, 2, 3, 4, 5, 6], [2, 4])).toEqual([1, 3, 5, 6]);
   });
 });

array/difference.ts

@@ -1,4 +1,4 @@
-export default (xs, ys) => {
+export default (xs: any[], ys: any[]) => {
   const zs = new Set(ys);
 
   return xs.filter(x => !zs.has(x));

array/differs.js

@@ -1,5 +1,5 @@
 export default (xs, ys) =>
-  (!xs && ys) ||
-  (!ys && xs) ||
+  Boolean(!xs && ys) ||
+  Boolean(!ys && xs) ||
   xs.length !== ys.length ||
   xs.some((x, index) => x !== ys[index]);

array/differs.json

@@ -1,6 +1,6 @@
 {
   "name": "differs",
-  "description": "TODO: Fill short description here.",
+  "description": "Checks if two arrays are not equal.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {

array/differs.md

@@ -1 +1,3 @@
 # differs
+
+Checks if two arrays are not equal.

array/differs.test.ts

@@ -3,7 +3,22 @@
 import differs from "./differs.ts";
 
 describe("differs", () => {
-  it.skip("TODO", () => {
-    expect(differs()).toBeDefined();
+  it("short-circuits over length differences", () => {
+    expect(differs([1, 2, 3], [1, 2])).toBe(true);
+    expect(differs([2, 3], [1, 2, 5])).toBe(true);
+  });
+
+  it("short-circuits over parameter presence", () => {
+    expect(differs(null, [1, 2])).toBe(true);
+    expect(differs([2, 3], undefined)).toBe(true);
+  });
+
+  it("compares elements index-wise", () => {
+    expect(differs([1, 2, 3], [1, 2, 3])).toBe(false);
+    expect(differs([1, 2, 3], [1, 67, 3])).toBe(true);
+  });
+
+  it("assumes empty arrays equal", () => {
+    expect(differs([], [])).toBe(false);
   });
 });

array/differs.ts

@@ -1,5 +1,5 @@
-export default (xs, ys) =>
-  (!xs && ys) ||
-  (!ys && xs) ||
+export default (xs?: any[], ys?: any[]) =>
+  Boolean(!xs && ys) ||
+  Boolean(!ys && xs) ||
   xs.length !== ys.length ||
   xs.some((x, index) => x !== ys[index]);

array/duplicates.json

@@ -1,6 +1,6 @@
 {
   "name": "duplicates",
-  "description": "TODO: Fill short description here.",
+  "description": "Lists all the duplicated values in the given array.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {

array/duplicates.md

@@ -1 +1,3 @@
 # duplicates
+
+Lists all the duplicated values in the given array.

array/duplicates.test.ts

@@ -3,7 +3,15 @@
 import duplicates from "./duplicates.ts";
 
 describe("duplicates", () => {
-  it.skip("TODO", () => {
-    expect(duplicates()).toBeDefined();
+  it("returns duplicated values", () => {
+    expect(duplicates([1, 2, 3, 4, 3, 5, 6, 7])).toEqual([3]);
+  });
+
+  it("returns all the duplicated values when there are any", () => {
+    expect(duplicates([1, 2, 3, 4, 3, 4, 3, 6])).toEqual([3, 4, 3]);
+  });
+
+  it("return an empty array when there are no duplicated", () => {
+    expect(duplicates([1, 2, 3, 4, 5, 6, 7, 8])).toEqual([]);
   });
 });

array/duplicates.ts

@@ -1,2 +1,2 @@
-export default xs =>
+export default (xs: any[]) =>
   xs.filter((value, index, self) => self.indexOf(value) !== index);

array/empty.json

@@ -1,6 +1,6 @@
 {
   "name": "empty",
-  "description": "TODO: Fill short description here.",
+  "description": "Empty array.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {

array/empty.md

@@ -1 +1,3 @@
 # empty
+
+Empty array.

array/empty.test.ts

@@ -3,7 +3,11 @@
 import empty from "./empty.ts";
 
 describe("empty", () => {
-  it.skip("TODO", () => {
-    expect(empty()).toBeDefined();
+  it("equals to the empty array", () => {
+    expect(empty).toEqual([]);
+  });
+
+  it("keeps the same reference", () => {
+    expect(empty).not.toBe([]);
   });
 });

array/exact.js

@@ -1,3 +1,3 @@
 import range from "./range.js";
 
-export default n => xs => range(n).map(index => xs[index]);
+export default count => xs => range(count).map(index => xs[index]);

array/exact.json

@@ -1,6 +1,6 @@
 {
   "name": "exact",
-  "description": "TODO: Fill short description here.",
+  "description": "Takes exactly the given count of elements.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {

array/exact.md

@@ -1 +1,3 @@
 # exact
+
+Takes exactly the given count of elements.

array/exact.test.ts

@@ -3,7 +3,7 @@
 import exact from "./exact.ts";
 
 describe("exact", () => {
-  it.skip("TODO", () => {
-    expect(exact()).toBeDefined();
+  it("takes exactly the given count of items and fills blanks with undefined values", () => {
+    expect(exact(5)([1, 2, 3])).toEqual([1, 2, 3, undefined, undefined]);
   });
 });

array/exact.ts

@@ -1,3 +1,4 @@
 import range from "./range";
 
-export default n => xs => range(n).map(index => xs[index]);
+export default (count: number) => (xs: any[]) =>
+  range(count).map(index => xs[index]);

array/except.json

@@ -1,6 +1,6 @@
 {
   "name": "except",
-  "description": "TODO: Fill short description here.",
+  "description": "Filters out the given value.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {

array/except.md

@@ -1 +1,3 @@
 # except
+
+Filters out the given value.

array/except.test.ts

@@ -3,7 +3,11 @@
 import except from "./except.ts";
 
 describe("except", () => {
-  it.skip("TODO", () => {
-    expect(except()).toBeDefined();
+  it("filters out the given value", () => {
+    expect(except(2)([1, 2, 3, 4, 5])).toEqual([1, 3, 4, 5]);
+  });
+
+  it("filters out multiple occurrences of the given value", () => {
+    expect(except(2)([1, 2, 2, 4, 2])).toEqual([1, 4]);
   });
 });

array/except.ts

@@ -1 +1 @@
-export default y => xs => xs.filter(x => x !== y);
+export default (y: any) => (xs: any[]) => xs.filter(x => x !== y);

array/filterInPlace.json

@@ -1,6 +1,6 @@
 {
   "name": "filterInPlace",
-  "description": "TODO: Fill short description here.",
+  "description": "Filters the given array with the given predicate just like Array.filter but does it in-place thus mutates the original array.",
   "signature": "TODO: Fill type signature here.",
   "examples": [
     {