feat(tslint): add support to read extended tslint.json

Closes: vvakame#123

Author: alan-agius4

lib/provider/tslintjson.ts

@@ -29,7 +29,7 @@ export interface AdditionalFormatSettings {
     $noConsecutiveBlankLines: boolean;
 }
 
-export function makeFormatCodeOptions(fileName: string, opts: Options, formatSettings: ts.FormatCodeSettings): ts.FormatCodeSettings {
+export async function makeFormatCodeOptions(fileName: string, opts: Options, formatSettings: ts.FormatCodeSettings): Promise<ts.FormatCodeSettings> {
 
     let baseDir = opts.baseDir ? path.resolve(opts.baseDir) : path.dirname(path.resolve(fileName));
     let configFileName: string | null;
@@ -46,20 +46,25 @@ export function makeFormatCodeOptions(fileName: string, opts: Options, formatSet
         console.log(`read ${configFileName} for ${fileName}`);
     }
 
-    let config: TslintSettings = parseJSON(fs.readFileSync(configFileName, "utf-8"));
-    if (!config.rules) {
+    const { Configuration } = await import("tslint");
+    const { rules } = Configuration.loadConfigurationFromPath(configFileName);
+
+    if (!rules) {
         return formatSettings;
     }
-    if (config.rules.indent && config.rules.indent[0]) {
-        if (config.rules.indent[1] === "spaces") {
+    const indent = rules.get("indent");
+    const whitespace = rules.get("whitespace");
+
+    if (indent && indent.ruleArguments) {
+        if (indent.ruleArguments[0] === "spaces") {
             formatSettings.convertTabsToSpaces = true;
-        } else if (config.rules.indent[1] === "tabs") {
+        } else if (indent.ruleArguments[0] === "tabs") {
             formatSettings.convertTabsToSpaces = false;
         }
     }
-    if (config.rules.whitespace && config.rules.whitespace[0]) {
-        for (let p in config.rules.whitespace) {
-            let value = config.rules.whitespace[p];
+    if (whitespace && whitespace.ruleArguments) {
+        for (let p in whitespace.ruleArguments) {
+            let value = whitespace.ruleArguments[p];
             if (value === "check-branch") {
                 formatSettings.insertSpaceAfterKeywordsInControlFlowStatements = true;
             } else if (value === "check-decl") {