feat: add whitespace character class

Author: jaworek

.gitignore

@@ -30,3 +30,5 @@ buck-out/
 
 # generated by bob
 lib/
+
+/.idea

src/__tests__/characterClasses.test.tsx

@@ -0,0 +1,9 @@
+import { whitespace } from '../characterClasses';
+import { buildPattern } from '../compiler';
+import { one } from '../quantifiers';
+
+test('"whitespace" character class', () => {
+  expect(buildPattern(whitespace())).toEqual(`\\s`);
+  expect(buildPattern(one('ab'), whitespace())).toEqual(`ab\\s`);
+  expect(buildPattern(one('ab'), whitespace(), one('c'))).toEqual(`ab\\sc`);
+});

src/characterClasses.ts

@@ -0,0 +1,5 @@
+import type { Whitespace } from './types';
+
+export function whitespace(): Whitespace {
+  return `\\s`;
+}

src/index.tsx

@@ -1,4 +1,5 @@
 export type * from './types';
 
+export { whitespace } from './characterClasses';
 export { buildRegex, buildPattern } from './compiler';
 export { oneOrMore, optionally } from './quantifiers';

src/types.ts

@@ -1,7 +1,12 @@
-export type RegexElement = string | RegexQuantifier;
+export type RegexElement = string | RegexCharacterClass | RegexQuantifier;
+
+export type RegexCharacterClass = Whitespace;
 
 export type RegexQuantifier = One | OneOrMore | Optionally | ZeroOrMore;
 
+// Character classes
+export type Whitespace = `\\s`;
+
 // Quantifiers
 export type One = {
   type: 'one';