support node 6

Author: Gerard Delmàs

src/DtsContent.ts

@@ -1,11 +1,8 @@
-import * as fs from "fs";
 import * as os from "os";
 import * as path from "path";
 import isThere from "is-there";
 import * as mkdirp from 'mkdirp';
-import * as util from "util";
-
-const writeFile = util.promisify(fs.writeFile);
+import {writeFile} from "./fs";
 
 
 interface DtsContentOptions {
@@ -74,7 +71,7 @@ export class DtsContent {
             mkdirp.sync(outPathDir);
         }
 
-        await writeFile(this.outputFilePath, this.formatted, 'utf8');
+        await writeFile(this.outputFilePath, this.formatted);
     }
 }
 

src/FileSystemLoader.ts

@@ -1,18 +1,15 @@
 /* this file is forked from https://raw.githubusercontent.com/css-modules/css-modules-loader-core/master/src/file-system-loader.js */
 
 import Core from 'css-modules-loader-core'
-import * as fs from 'fs'
 import * as path from 'path'
-import * as util from 'util'
 import { Plugin } from "postcss";
+import {readFile} from "./fs";
 
 
 type Dictionary<T> = {
   [key: string]: T | undefined;
 };
 
-const readFile = util.promisify(fs.readFile);
-
 
 export default class FileSystemLoader {
   private root: string;
@@ -54,7 +51,7 @@ export default class FileSystemLoader {
       }
 
       try {
-        source = await readFile(fileRelativePath, "utf-8");
+        source = await readFile(fileRelativePath);
       }
       catch (error) {
         if (relativeTo && relativeTo !== '/') {

src/fs.ts

@@ -0,0 +1,28 @@
+import * as fs from 'fs';
+
+
+export function readFile(path: fs.PathLike): Promise<string> {
+    return new Promise<string>((resolve, reject) => {
+        fs.readFile(path, 'utf-8', (err, data) => {
+            if (err !== null) {
+                reject(err);
+                return;
+            }
+
+            resolve(data);
+        });
+    });
+}
+
+export function writeFile(path: fs.PathLike, data: string): Promise<void> {
+    return new Promise<void>((resolve, reject) => {
+        fs.writeFile(path, data, 'utf-8', (err) => {
+            if (err !== null) {
+                reject(err);
+                return;
+            }
+
+            resolve();
+        });
+    });
+}