diff --git a/TODO.md b/TODO.md
new file mode 100644
index 0000000..1d0ae73
--- /dev/null
+++ b/TODO.md
@@ -0,0 +1,3 @@
+- [ ] Ordinals
+- [ ] Fractions
+- [ ] Other locales (long count, languages, etc.)
diff --git a/packages/core/.eslintrc b/packages/core/.eslintrc
index 35cfb79..e479339 100644
--- a/packages/core/.eslintrc
+++ b/packages/core/.eslintrc
@@ -1,5 +1,9 @@
 {
   "root": true,
+	"rules": {
+		"indent": ["error", "tab"],
+		"no-tabs": "off"
+	},
   "extends": [
     "lxsmnsyc/typescript"
   ],
diff --git a/packages/core/.gitignore b/packages/core/.gitignore
index 53992de..bea7415 100644
--- a/packages/core/.gitignore
+++ b/packages/core/.gitignore
@@ -105,3 +105,4 @@ dist
 .tern-port
 
 .npmrc
+types/
diff --git a/packages/core/src/converter.ts b/packages/core/src/converter.ts
index ec5b09c..f4ccb47 100644
--- a/packages/core/src/converter.ts
+++ b/packages/core/src/converter.ts
@@ -10,14 +10,14 @@ export interface StringifyOptions {
 
 export const stringify = (
 	valueRaw: StringifyValue,
-	options = {} as StringifyOptions
+	options = {} as StringifyOptions,
 ): string => {
 	if (!(['bigint', 'number', 'string'].includes(typeof (valueRaw as unknown)))) {
 		throw new TypeError('value must be a string, number, or bigint');
 	}
 
 	const value = valueRaw.toString().replace(/\s/g, '');
-	const { system = enUS, makeGroupOptions} = options;
+	const { system = enUS, makeGroupOptions } = options;
 
 	if (value.startsWith('-')) {
 		return system.makeNegative(stringify(value.slice(1), options));
@@ -47,12 +47,12 @@ export const parse = (value: string, options = {} as ParseOptions) => {
 	const stringValue = system.combineGroups(groups);
 
 	switch (type) {
-		case 'number':
-			return Number(stringValue);
-		case 'bigint':
-			return BigInt(stringValue);
-		default:
-			break;
+	case 'number':
+		return Number(stringValue);
+	case 'bigint':
+		return BigInt(stringValue);
+	default:
+		break;
 	}
 
 	return stringValue;
diff --git a/packages/core/src/exponent.ts b/packages/core/src/exponent.ts
index 0b29d36..a4dad5f 100644
--- a/packages/core/src/exponent.ts
+++ b/packages/core/src/exponent.ts
@@ -26,7 +26,10 @@ export interface NumberToExponentialOptions {
  * @param value - The string value to extract components from.
  * @param options - Options to use when extracting components.
  */
-export const extractExponentialComponents = (value: string, options = {} as NumberToExponentialOptions) => {
+export const extractExponentialComponents = (
+	value: string,
+	options = {} as NumberToExponentialOptions,
+) => {
 	const {
 		decimalPoint = '.',
 		groupingSymbol = ',',
@@ -67,15 +70,18 @@ export const extractExponentialComponents = (value: string, options = {} as Numb
 		exponent: exponentValue < 0 ? exponentValue.toString() : `+${exponentValue}`,
 		fractional,
 	};
-}
+};
 
 /**
  * Converts a numeric value to a string in exponential notation. Supports numbers of all types.
  * @param value - The value to convert.
  * @param options - Options to use when extracting components.
  */
-export const numberToExponential = (value: ValidValue, options = {} as NumberToExponentialOptions): string => {
-	const stringValueRaw = value as unknown
+export const numberToExponential = (
+	value: ValidValue,
+	options = {} as NumberToExponentialOptions,
+): string => {
+	const stringValueRaw = value as unknown;
 
 	if (typeof stringValueRaw === 'bigint' || typeof stringValueRaw === 'number') {
 		return numberToExponential(stringValueRaw.toString(), options);