add typings for async getSource and runtime.SafeString class

types/nunjucks/index.d.ts

@@ -94,7 +94,7 @@ export function installJinjaCompat(): void;
 
 export interface ILoader {
     async?: boolean;
-    getSource(name: string): LoaderSource;
+    getSource(name: string, callback?: (err?: any, result?: LoaderSource) => void): LoaderSource | void;
     extend?(extender: ILoader): ILoader;
 }
 
@@ -137,3 +137,9 @@ export class PrecompiledLoader extends Loader implements ILoader {
     init(searchPaths: string[], opts: any): void;
     getSource(name: string): LoaderSource;
 }
+
+export namespace runtime {
+    class SafeString {
+        constructor(...args: any[]);
+    }
+}

types/nunjucks/nunjucks-tests.ts

@@ -52,3 +52,5 @@ class MyLoader extends nunjucks.Loader implements nunjucks.ILoader {
 }
 
 env = new nunjucks.Environment(new MyLoader());
+
+new nunjucks.runtime.SafeString();

types/nunjucks/tslint.json

@@ -1,6 +1,7 @@
 {
     "extends": "dtslint/dt.json",
     "rules": {
-        "interface-name": false
+        "interface-name": false,
+        "no-unnecessary-class": false // to allow SafeString class
     }
 }