Update tslib to support new __spreadArray helper

Author: rbuckton

tslib.d.ts

@@ -23,8 +23,11 @@ export declare function __generator(thisArg: any, body: Function): any;
 export declare function __exportStar(m: any, o: any): void;
 export declare function __values(o: any): any;
 export declare function __read(o: any, n?: number): any[];
+/** @deprecated since TypeScript 4.2 */
 export declare function __spread(...args: any[][]): any[];
+/** @deprecated since TypeScript 4.2 */
 export declare function __spreadArrays(...args: any[][]): any[];
+export declare function __spreadArray(to: any[], from: any[]): any[];
 export declare function __await(v: any): any;
 export declare function __asyncGenerator(thisArg: any, _arguments: any, generator: Function): any;
 export declare function __asyncDelegator(o: any): any;

tslib.es6.js

@@ -144,19 +144,27 @@ export function __read(o, n) {
     return ar;
 }
 
+/** @deprecated */
 export function __spread() {
     for (var ar = [], i = 0; i < arguments.length; i++)
         ar = ar.concat(__read(arguments[i]));
     return ar;
 }
 
+/** @deprecated */
 export function __spreadArrays() {
     for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
     for (var r = Array(s), k = 0, i = 0; i < il; i++)
         for (var a = arguments[i], j = 0, jl = a.length; j < jl; j++, k++)
             r[k] = a[j];
     return r;
-};
+}
+
+export function __spreadArray(to, from) {
+    for (var i = 0, il = from.length, j = to.length; i < il; i++, j++)
+        to[j] = from[i];
+    return to;
+}
 
 export function __await(v) {
     return this instanceof __await ? (this.v = v, this) : new __await(v);

tslib.js

@@ -26,6 +26,7 @@ var __values;
 var __read;
 var __spread;
 var __spreadArrays;
+var __spreadArray;
 var __await;
 var __asyncGenerator;
 var __asyncDelegator;
@@ -184,12 +185,14 @@ var __createBinding;
         return ar;
     };
 
+    /** @deprecated */
     __spread = function () {
         for (var ar = [], i = 0; i < arguments.length; i++)
             ar = ar.concat(__read(arguments[i]));
         return ar;
     };
 
+    /** @deprecated */
     __spreadArrays = function () {
         for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
         for (var r = Array(s), k = 0, i = 0; i < il; i++)
@@ -198,6 +201,12 @@ var __createBinding;
         return r;
     };
 
+    __spreadArray = function (to, from) {
+        for (var i = 0, il = from.length, j = to.length; i < il; i++, j++)
+            to[j] = from[i];
+        return to;
+    };
+
     __await = function (v) {
         return this instanceof __await ? (this.v = v, this) : new __await(v);
     };
@@ -280,6 +289,7 @@ var __createBinding;
     exporter("__read", __read);
     exporter("__spread", __spread);
     exporter("__spreadArrays", __spreadArrays);
+    exporter("__spreadArray", __spreadArray);
     exporter("__await", __await);
     exporter("__asyncGenerator", __asyncGenerator);
     exporter("__asyncDelegator", __asyncDelegator);