Escape special characters in generated pattern

Install escape-string-regexp to escape any characters with special
meaning in RegEx before adding them to the pattern.

Author: wimpyprogrammer

package.json

@@ -40,6 +40,7 @@
     "@babel/core": "^7.5.5",
     "@babel/preset-env": "^7.5.5",
     "@babel/preset-typescript": "^7.5.5",
+    "@types/escape-string-regexp": "^1.0.0",
     "@types/jest": "^24.0.18",
     "@types/jest-when": "^2.7.0",
     "@typescript-eslint/eslint-plugin": "^2.2.0",
@@ -61,5 +62,8 @@
     "typescript": "^3.6.3",
     "webpack": "^4.17.2",
     "webpack-command": "^0.4.1"
+  },
+  "dependencies": {
+    "escape-string-regexp": "^1.0.0"
   }
 }

src/utils/pattern.spec.ts

@@ -47,6 +47,14 @@ describe('build', () => {
 		expect(build(trie)).toBe('foo bar');
 	});
 
+	it('escapes characters with special meaning in RegEx', () => {
+		const specialChars = String.raw`foo.?+|(){}^$\[]bar`;
+		const trie = CharTrie.create({ [specialChars]: {} });
+
+		const pattern = String.raw`foo\.\?\+\|\(\)\{\}\^\$\\\[\]bar`;
+		expect(build(trie)).toBe(pattern);
+	});
+
 	it('processes complex trie', () => {
 		const trie = CharTrie.create({
 			M: {

src/utils/pattern.ts

@@ -1,3 +1,4 @@
+import escapeStringRegexp from 'escape-string-regexp';
 import { CharTrie } from '../types/charTrie';
 
 /**
@@ -10,7 +11,7 @@ import { CharTrie } from '../types/charTrie';
 export function build(charTrie: CharTrie): string {
 	const patternSegments = Array.from(
 		[...charTrie],
-		([head, suffixTrie]) => `${head}${build(suffixTrie)}`
+		([head, suffixTrie]) => `${escapeStringRegexp(head)}${build(suffixTrie)}`
 	);
 
 	let pattern = patternSegments.join('|');

tsconfig.json

@@ -1,9 +1,9 @@
 {
 	"compilerOptions": {
 		"allowJs": true,
-		"allowSyntheticDefaultImports": true,
 		"baseUrl": "./",
 		"downlevelIteration": true,
+		"esModuleInterop": true,
 		"rootDir": "./",
 		"lib": [
 			"es5",

yarn.lock

@@ -880,6 +880,11 @@
   dependencies:
     "@babel/types" "^7.3.0"
 
+"@types/escape-string-regexp@^1.0.0":
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/@types/escape-string-regexp/-/escape-string-regexp-1.0.0.tgz#052d16d87db583b72daceae4eaabddb66954424c"
+  integrity sha512-KAruqgk9/340M4MYYasdBET+lyYN8KMXUuRKWO72f4SbmIMMFp9nnJiXUkJS0HC2SFe4x0R/fLozXIzqoUfSjA==
+
 "@types/eslint-visitor-keys@^1.0.0":
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/@types/eslint-visitor-keys/-/eslint-visitor-keys-1.0.0.tgz#1ee30d79544ca84d68d4b3cdb0af4f205663dd2d"
@@ -2520,7 +2525,7 @@ es6-symbol@^3.1.1, es6-symbol@~3.1.1:
     d "^1.0.1"
     es5-ext "^0.10.51"
 
-escape-string-regexp@^1.0.5:
+escape-string-regexp@^1.0.0, escape-string-regexp@^1.0.5:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/escape-string-regexp/-/escape-string-regexp-1.0.5.tgz#1b61c0562190a8dff6ae3bb2cf0200ca130b86d4"
   integrity sha1-G2HAViGQqN/2rjuyzwIAyhMLhtQ=