Code cleanup

src/index.mjs

@@ -10,7 +10,6 @@ import {
 	sourceMapRebase,
 	pathRelativeIfSub,
 	stringAbbrev,
-	stringOrBufferCast,
 	readFileAsync
 } from './util';
 import {data} from './uri';
@@ -84,9 +83,9 @@ export default async function (source, map, meta) {
 	const resolverMulti = createResolverMulti(resolver);
 
 	// If passed a buffer then convert to a string or emit warning and skip.
-	let sourceString = null;
+	let text;
 	try {
-		sourceString = stringOrBufferCast(source, 'utf8');
+		text = typeof source === 'string' ? source : source.toString('utf8');
 	} catch (err) {
 		emitWarning(new Exception(`Failed to cast source to string: ${err}`));
 		// eslint-disable-next-line prefer-rest-params
@@ -95,7 +94,7 @@ export default async function (source, map, meta) {
 	}
 
 	// Parse source map comment or pass the arguments straight through.
-	const parsed = commentParse(sourceString);
+	const parsed = commentParse(text);
 	if (!parsed) {
 		// eslint-disable-next-line prefer-rest-params
 		callback(null, ...arguments);
@@ -126,7 +125,7 @@ export default async function (source, map, meta) {
 
 		// Attempt to decode source map content.
 		try {
-			mapCode = dataURI.body().toString(dataURI.charset);
+			mapCode = dataURI.text();
 		} catch (err) {
 			emitWarning(
 				new Exception(`Failed to decode data URI: ${mapInfo}: ${err}`)

src/uri.mjs

@@ -1,3 +1,5 @@
+const US_ASCII = 'US-ASCII';
+
 /**
  * Decode percents in string.
  *
@@ -32,7 +34,7 @@ export function data(uri) {
 		: mediaInfo;
 	const [mimeType] = mediaType.split(';', 1);
 	const m2 = mediaType.match(/;charset=([^;]*)(;|$)/iu);
-	const charset = (m2 ? m2[1] : '') || 'US-ASCII';
+	const charset = (m2 ? m2[1] : '') || US_ASCII;
 	return {
 		mediaType,
 		mimeType,
@@ -47,8 +49,20 @@ export function data(uri) {
 		 */
 		body() {
 			return Buffer.from(
-				decodePercents(data),
-				base64 ? 'base64' : 'utf8'
+				decodePercents(this.data),
+				this.base64 ? 'base64' : 'utf8'
+			);
+		},
+
+		/**
+		 * Get body as text.
+		 *
+		 * @returns {string} Text data.
+		 */
+		text() {
+			const {charset} = this;
+			return this.body().toString(
+				charset.toUpperCase() === US_ASCII ? 'ascii' : charset
 			);
 		}
 	};

src/uri.spec.mjs

@@ -36,7 +36,7 @@ for (const [uri, info] of [
 			strictEqual(d.charset, info.charset);
 			strictEqual(d.base64, info.base64);
 			strictEqual(d.data, info.data);
-			strictEqual(d.body().toString(), info.body);
+			strictEqual(d.text(), info.body);
 		} else {
 			strictEqual(d, null);
 		}

src/util.mjs

@@ -140,20 +140,6 @@ export function decodeURISafe(str) {
 	return null;
 }
 
-/**
- * Convert string or Buffer to string.
- *
- * @param {string|Buffer} data String or Buffer data.
- * @param {string} encoding Buffer encoding.
- * @returns {string} String value.
- */
-export function stringOrBufferCast(data, encoding = 'utf8') {
-	if (typeof data === 'string') {
-		return data;
-	}
-	return data.toString(encoding);
-}
-
 /**
  * Read a file asyncronousely.
  *

src/util.spec.mjs

@@ -11,7 +11,6 @@ import {
 	pathRelativeIfSub,
 	stringAbbrev,
 	decodeURISafe,
-	stringOrBufferCast,
 	readFileAsync
 } from './util';
 
@@ -255,14 +254,6 @@ test('decodeURISafe: invalid', () => {
 	strictEqual(decodeURISafe('%%'), null);
 });
 
-test('stringOrBufferCast: string', () => {
-	strictEqual(stringOrBufferCast('hello'), 'hello');
-});
-
-test('stringOrBufferCast: buffer', () => {
-	strictEqual(stringOrBufferCast(Buffer.from('hello')), 'hello');
-});
-
 test('readFileAsync: pass', async () => {
 	const pkg = JSON.parse(await readFileAsync('package.json', 'utf8'));
 	strictEqual(typeof pkg, 'object');