fix(typos): fix typos in chapters 13 to 15

Author: gdarchen

book-content/chapters/13-modules-scripts-declaration-files.md

@@ -383,12 +383,12 @@ declare module "duration-utils" {
 
 We use `export` to define what is being exported from the module.
 
-Like before, we are not including any implementation code in the `.d.ts` file– it's just the types that are being declared.
+Like before, we are not including any implementation code in the `.d.ts` file – it's just the types that are being declared.
 
 Once the `duration-utils.d.ts` file is created, the module can be imported and used as usual:
 
 ```typescript
-import { formatDuration, parseTrackData } from "music-utils";
+import { formatDuration, parseTrackData } from "duration-utils";
 
 const formattedTime = formatDuration(309);
 ```
@@ -468,7 +468,7 @@ const numbers = [1, 2, 3];
 numbers.map((n) => n * 2);
 ```
 
-Let's step back for a minute. How does TypeScript know that `.map` exists on an array? How does it know that `.map` exists, but `.transform` doesn't? Where is this defined
+Let's step back for a minute. How does TypeScript know that `.map` exists on an array? How does it know that `.map` exists, but `.transform` doesn't? Where is this defined?
 
 As it turns out, TypeScript ships with a bunch of declaration files that describe the JavaScript environment. We can do a 'go to definition' on `.map` to see where that is:
 

book-content/chapters/14-configuring-typescript.md

@@ -909,7 +909,7 @@ The common settings can be moved to `tsconfig.base.json`:
 }
 ```
 
-Then, the `client/tsconfig.json` would extend the base configuration wit the `extends` option that points to the `tsconfig.base.json` file:
+Then, the `client/tsconfig.json` would extend the base configuration with the `extends` option that points to the `tsconfig.base.json` file:
 
 ```tsx
 // client/tsconfig.json

book-content/chapters/15-designing-your-types.md

@@ -232,7 +232,7 @@ TypeScript shows an error that tells us that `ResourceStatus` requires two type
 
 In some cases, you may want to provide default types for generic type parameters. Like with functions, you can use the `=` to assign a default value.
 
-By setting `TMetadata`'s default value to an empty, we can essentially make `TMetadata` optional:
+By setting `TMetadata`'s default value to an empty object, we can essentially make `TMetadata` optional:
 
 ```tsx
 type ResourceStatus<TContent, TMetadata = {}> =
@@ -549,7 +549,7 @@ Conditional types turn TypeScript's type system into a full programming language
 
 ## Mapped Types
 
-Mapped types in TypeScript allow you to create a new object type based on an existing type by iterating over its keys and values. This can be let you be extremely expressive when creating new object types.
+Mapped types in TypeScript allow you to create a new object type based on an existing type by iterating over its keys and values. This can let you be extremely expressive when creating new object types.
 
 Consider this `Album` interface: