cocos create 2.1.2，构建微信小游戏时，勾选了Source Maps后会报错导致构建失败。错误信息如下：
Build Failed: TypeError: Cannot read property ‘0’ of null
at C:\CocosCreator_2.1.2\resources\app.asar\editor\page\refine-sourcemap.js:1:1466
at u (C:\CocosCreator_2.1.2\resources\app.asar\editor\page\refine-sourcemap.js:1:1480)
at Stream. (C:\CocosCreator_2.1.2\resources\app.asar\editor\page\refine-sourcemap.js:1:1597)
at Stream.stream.write (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\through\index.js:26:11)
at DestroyableTransform.ondata (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_readable.js:619:20)
at emitOne (events.js:96:13)
at DestroyableTransform.emit (events.js:191:7)
at addChunk (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_readable.js:291:12)
at readableAddChunk (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_readable.js:278:11)
at DestroyableTransform.Readable.push (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_readable.js:245:10)
at DestroyableTransform.Transform.push (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_transform.js:148:32)
at DestroyableTransform.afterTransform (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\readable-stream\lib_stream_transform.js:91:10)
at r.waterfall.r (C:\CocosCreator_2.1.2\resources\app.asar\editor\lib\builder\index.js:1:3393)
at C:\CocosCreator_2.1.2\resources\app.asar\node_modules\async\lib\async.js:52:16
at C:\CocosCreator_2.1.2\resources\app.asar\node_modules\async\lib\async.js:696:30
at C:\CocosCreator_2.1.2\resources\app.asar\node_modules\async\lib\async.js:167:37
at C:\CocosCreator_2.1.2\resources\app.asar\node_modules\async\lib\async.js:1209:30
at Gulp.doneCallback (C:\CocosCreator_2.1.2\resources\app.asar\editor\core\gulp-build.js:1:29766)
at Gulp.Orchestrator.stop (C:\CocosCreator_2.1.2\resources\app.asar\node_modules\orchestrator\index.js:150:9)
at C (C:\CocosCreator_2.1.2\resources\app.asar\editor\core\gulp-build.js:1:6396)
at C:\CocosCreator_2.1.2\resources\app.asar\editor\core\gulp-build.js:1:8506
请问是什么原因？我应该怎么解决？