diff --git a/src/lib/es5.d.ts b/src/lib/es5.d.ts
index 6decc78558a..48a97fa6658 100644
--- a/src/lib/es5.d.ts
+++ b/src/lib/es5.d.ts
@@ -1635,7 +1635,7 @@ interface Int8Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Int8Array) => number, thisArg: any): Int8Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Int8Array) => number, thisArg?: any): Int8Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -1902,7 +1902,7 @@ interface Uint8Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Uint8Array) => number, thisArg: any): Uint8Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Uint8Array) => number, thisArg?: any): Uint8Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -2169,7 +2169,7 @@ interface Uint8ClampedArray {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Uint8ClampedArray) => number, thisArg: any): Uint8ClampedArray;
+    map(callbackfn: (this: void, value: number, index: number, array: Uint8ClampedArray) => number, thisArg?: any): Uint8ClampedArray;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -2434,7 +2434,7 @@ interface Int16Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Int16Array) => number, thisArg: any): Int16Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Int16Array) => number, thisArg?: any): Int16Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -2702,7 +2702,7 @@ interface Uint16Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Uint16Array) => number, thisArg: any): Uint16Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Uint16Array) => number, thisArg?: any): Uint16Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -3235,7 +3235,7 @@ interface Uint32Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Uint32Array) => number, thisArg: any): Uint32Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Uint32Array) => number, thisArg?: any): Uint32Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of
@@ -3502,7 +3502,7 @@ interface Float32Array {
       * @param thisArg An object to which the this keyword can refer in the callbackfn function.
       * If thisArg is omitted, undefined is used as the this value.
       */
-    map(callbackfn: (this: void, value: number, index: number, array: Float32Array) => number, thisArg: any): Float32Array;
+    map(callbackfn: (this: void, value: number, index: number, array: Float32Array) => number, thisArg?: any): Float32Array;
 
     /**
       * Calls the specified callback function for all the elements in an array. The return value of