Update tsc check to read from config if present

See microsoft/TypeScript#5858, fixes neomake#200. Thanks to @HerringtonDarkholme for doing all the work.

Author: faceleg

autoload/neomake/makers/ft/typescript.vim

@@ -4,11 +4,54 @@ function! neomake#makers#ft#typescript#EnabledMakers()
     return ['tsc', 'tslint']
 endfunction
 
+let s:enabled_options = [
+    \ 'target',
+    \ 'emitDecoratorMetadata',
+    \ 'experimentalDecorators',
+    \ 'module',
+    \ 'noImplicitAny',
+    \ 'rootDir',
+    \ 'noEmit',
+    \ 'allowSyntheticDefaultImports',
+    \ 'noImplicitReturn',
+    \ 'allowUnreachableCode',
+    \ 'allowUnusedLabels'
+    \ ]
+
 function! neomake#makers#ft#typescript#tsc()
+    let l:tsconfig = findfile('tsconfig.json', '.;')
+    if len(l:tsconfig)
+        let true = 1
+        let false = 0
+        let null = 0
+        " ugly shortcut
+        let l:jsonText = join(readfile(l:tsconfig, 'b'), '')
+        let l:json = eval(l:jsonText)
+        let l:option = get(l:json, 'compilerOptions', {})
+        let l:option['noEmit'] = 1
+        let l:args = []
+        if !len(get(l:option, 'rootDir', ''))
+            let l:option['rootDir'] = fnamemodify(l:tsconfig, ':h')
+        endif
+        for [key, value] in items(l:option)
+            if index(s:enabled_options, key) == -1
+                continue
+            endif
+            if value == 1
+                call insert(l:args, '--'.key)
+            elseif type(value) == type('')
+                call insert(l:args, value)
+                call insert(l:args, '--'.key)
+            endif
+        endfor
+    else
+        let l:args = [
+            \ '-m', 'commonjs', '--noEmit', '--rootDir', '.'
+        \ ]
+    endif
+
     return {
-        \ 'args': [
-            \ '-m', 'commonjs', '--noEmit'
-        \ ],
+        \ 'args': l:args,
         \ 'errorformat':
             \ '%E%f %#(%l\,%c): error %m,' .
             \ '%E%f %#(%l\,%c): %m,' .