fix: fix sourcesContent format

Author: 3cp

spec/shared.read-source-map.spec.js

@@ -12,6 +12,7 @@ test('getSourceMap gets referenced sourceMap file content', t => {
   t.deepEqual(sourceMap.sources, ['src/x.js']);
   t.ok(sourceMap.sourcesContent);
   t.equal(sourceMap.sourcesContent.length, 1);
+  t.equal(typeof sourceMap.sourcesContent[0], 'string');
   t.ok(sourceMap.sourcesContent[0].includes('_.trim'));
   t.end();
 });

src/shared.js

@@ -130,7 +130,7 @@ export function getSourceMap(contents, filePath) {
       // bring in sources content inline
       try {
         sourceMap.sourcesContent = sourceMap.sources.map(s =>
-          fs.readFileSync(path.resolve(dir, s))
+          fs.readFileSync(path.resolve(dir, s), 'utf8')
         );
       } catch (err) {
         //