resolveAppScriptPath() is not pass scriptExtensions to fixFileExtensions()

[ebbnormal]

When working with the following middleware/ directory structure:

middleware / 
   verison.js
   version.js.map

when we run the server, loopback tries to execute the file with the extension .map as if it were a middleware factory with a .js extension.

Here is the stack trace which is produced when running the loopback server.

/Users/server/build/middleware/version.js.map:1
(function (exports, require, module, __filename, __dirname) { {"version":3,"file":"version.js","sourceRoot":"/Users/angular2-loopback-starter/server/src/","sources":["middleware/version.ts"],"names":[],"mappings":";AAAA,+CAAsC;AACtC,IAAI,UAAU,GAAG,OAAO,CAAC,uBAAuB,CAAC,CAAC,OAAO,CAAC;AAE1D,IAAI,UAAU,GAAG,IAAI,CAAC;AAEtB,oBAAI,CAAC,4BAA4B,EAAE,UAAC,KAAK,EAAE,MAAM,EAAE,MAAM;IACvD,UAAU,GAAG,MAAM,CAAC,IAAI,EAAE,CAAC;AAC7B,CAAC,CAAC,CAAC;AAEH,iBAAS;IACP,MAAM,CAAC,UAAC,GAAG,EAAE,GAAG,EAAE,IAAI;QACpB,GAAG,CAAC,MAAM,CAAC,WAAW,EAAE,UAAU,GAAG,IAAI,GAAG,UAAU,GAAG,GAAG,CAAC,CAAC;QAC9D,IAAI,EAAE,CAAC;IACT,CAAC,CAAC;AACJ,CAAC,CAAC"}
                                                                        ^
SyntaxError: Unexpected token :
    at Object.exports.runInThisContext (vm.js:76:16)
    at Module._compile (module.js:542:28)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.require (module.js:497:17)
    at require (internal/module.js:20:19)
    at /Users/node_modules/loopback-boot/lib/executor.js:343:19
    at Array.forEach (native)
    at setupMiddleware (/Users/node_modules/loopback-boot/lib/executor.js:340:14)
    at execute (/Users/node_modules/loopback-boot/lib/executor.js:40:3)
    at bootLoopBackApp (/Users/node_modules/loopback-boot/index.js:154:3)
    at Object.<anonymous> (/Users/server/build/server.js:7:1)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)

We tried to do a workaround by including the new options variable to boot() by adding the scriptExtensions [".js"]. We thought this would exclude the .map file being executed in the middleware directory. However, when we debugged it, we saw that the scriptExtensions was undefined at the moment of filtering out files based on extensions. We traced this back to fixFileExtensions not received the options.scriptExtensions.

[ebbnormal]

#279 @bajtos Here is my patch. I am not sure whether or not the middleware object though is simply the sourceFile or a string, so the comparison may be off, feedback most welcome!

[bajtos]

This issue has been fixed by #263 in loopback-boot@2.26.2