Fix some typos (#3)

* separate interface entries with semicolon

* mistype trueIfSome

* generic expected after func name

* export toPositiveInteger for testing purpose

* mix up 'constant' function typings'

* without webpack config default entry point src/index.js

* update constant function type in comments

* grammar fix

Co-authored-by: Lee Newson <[email protected]>

* remove non-relevant comment block

Co-authored-by: Lee Newson <[email protected]>

Author: vpyshnenko

src/index.js

@@ -0,0 +1 @@
+// Dummy entry point for webpack.

src/main/ts/Part2Ex2ArrayFunctions.ts

@@ -27,9 +27,9 @@ Let's set up some dummy test data to talk about frogs, and write some code about
  */
 
 export interface Frog {
-  readonly name: string,
-  readonly ribbits: boolean,
-  readonly age: number
+  readonly name: string;
+  readonly ribbits: boolean;
+  readonly age: number;
 }
 
 export const myFrogs: Frog[] = [
@@ -61,7 +61,7 @@ export const runMap1 = (xs: number[]): number[] =>
 
 // prepend a string to each element
 export const runMap2 = (xs: number[]): string[] =>
-  Arr.map(xs, (x) => "the number is " + 1);
+  Arr.map(xs, (x) => "the number is " + x);
 
 // TODO: Return the frog's names and check it by running
 // yarn bedrock-auto -b chrome-headless -f src/test/ts/Exercise2ArrayFunctionsTest.ts

src/main/ts/Part2Ex3Optional.ts

@@ -32,7 +32,7 @@ const parseIntOpt = (s: string): Optional<number> => {
   return Number.isNaN(n) ? Optional.some(n) : Optional.none();
 };
 
-const toPositiveInteger = (n: number): Optional<number> =>
+export const toPositiveInteger = (n: number): Optional<number> =>
   n > 0 ? Optional.some(n) : Optional.none();
 
 // TODO: create a function which takes a string and returns some if the string is non-empty
@@ -83,7 +83,7 @@ export const message = (e: Optional<string>): string =>
 // TODO: Implement a function using fold, that takes an Optional<number>. If it's some, double it. If it's none, return 0;
 
 // TODO: Implement a function that takes an Optional<T> for any type T. Return true if it's some, and false if it's none.
-const trueIfSome = <T> (x: T): Optional<T> => {
+const trueIfSome = <T> (x: Optional<T>): boolean  => {
   throw new Error("TODO");
 };
 
@@ -147,7 +147,7 @@ Some examples, then some exercises:
 
 const x: Optional<string> = Optional.some(3).map((x) => String(x)); // returns Optional.some("3")
 
-const y: Optional<string> = Optional.none<number>().map((x) => String(x)); // returns Optional.<string>none()
+const y: Optional<string> = Optional.none<number>().map((x) => String(x)); // returns Optional.none<string>()
 
 // TODO: Write a function that takes an Optional<number> and adds 3 to the number
 

src/main/ts/Part2Ex4FP.ts

@@ -143,7 +143,7 @@ const constant = <A> (a: A) => (...args: unknown[]): A => a;
 const always3 = constant(3);
 
 /*
-So, constant ignores whatever is passed for the B parameter, and just returns the A.
+So, constant ignores whatever is passed for input parameters, and just returns the A.
 
 Again, this looks familiar from our getOrElse1 function above.
 
@@ -152,15 +152,7 @@ TODO: rewrite getOrElse1 using both Fun.identity and the "constant" function def
 
 
 /*
-Now, katamari's Fun.constant is slightly different to ours above:
-
-const constant = <A, B> (a: A) => (b: B) => a; // ours
-const constant = <A> (a: A) => () => a;        // katamari's
-
-In most languages, this would be make the two incompatible. However, TypeScript is a bit more lenient and lets us
-use the second form everywhere the first form is expected.
-
-TODO: don't just take my word for it - use katamari's Fun.constant in you getOrElse and see if it compiles.
+TODO: use katamari's Fun.constant in your getOrElse and see if it compiles.
  */
 
 // TODO: Write a function that takes an array of numbers and replaces each value with 9.
@@ -222,4 +214,3 @@ signature and handling for n-ary functions. Your rule-of-thumb is to use Fun.com
 // TODO: Rewrite this function to use a single map call and function composition
 const dblOs = (oa: Optional<number>): Optional<string> =>
   oa.map(dbl).map(String);
-