Add the Omit helper type

src/harness/fourslash.ts

@@ -4507,6 +4507,7 @@ namespace FourSlashInterface {
             typeEntry("Record"),
             typeEntry("Exclude"),
             typeEntry("Extract"),
+            typeEntry("Omit"),
             typeEntry("NonNullable"),
             typeEntry("Parameters"),
             typeEntry("ConstructorParameters"),

src/lib/es5.d.ts

@@ -1443,6 +1443,11 @@ type Exclude<T, U> = T extends U ? never : T;
  */
 type Extract<T, U> = T extends U ? T : never;
 
+/**
+ * Construct a type with the properties of T except for those in type K.
+ */
+type Omit<T, K extends keyof any> = Pick<T, Exclude<keyof T, K>>;
+
 /**
  * Exclude null and undefined from T
  */

tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.js

@@ -45,10 +45,14 @@ const myStoreConnect: Connect = function(
         mergeProps,
         options,
     );
-};
+};
+
+export {};
+
 
 //// [circularlySimplifyingConditionalTypesNoCrash.js]
 "use strict";
+exports.__esModule = true;
 var myStoreConnect = function (mapStateToProps, mapDispatchToProps, mergeProps, options) {
     if (options === void 0) { options = {}; }
     return connect(mapStateToProps, mapDispatchToProps, mergeProps, options);

tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.symbols

@@ -152,3 +152,6 @@ const myStoreConnect: Connect = function(
 
     );
 };
+
+export {};
+

tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types

@@ -90,3 +90,6 @@ const myStoreConnect: Connect = function(
 
     );
 };
+
+export {};
+

tests/baselines/reference/indexedAccessRetainsIndexSignature.js

@@ -8,8 +8,10 @@ type Omit1<U, K extends keyof U> = Pick<U, Diff<keyof U, K>>;
 type Omit2<T, K extends keyof T> = {[P in Diff<keyof T, K>]: T[P]};
 
 type O = Omit<{ a: number, b: string }, 'a'>
-const o: O = { b: '' }
+export const o: O = { b: '' }
 
 
 //// [indexedAccessRetainsIndexSignature.js]
-var o = { b: '' };
+"use strict";
+exports.__esModule = true;
+exports.o = { b: '' };

tests/baselines/reference/indexedAccessRetainsIndexSignature.symbols

@@ -55,8 +55,8 @@ type O = Omit<{ a: number, b: string }, 'a'>
 >a : Symbol(a, Decl(indexedAccessRetainsIndexSignature.ts, 8, 15))
 >b : Symbol(b, Decl(indexedAccessRetainsIndexSignature.ts, 8, 26))
 
-const o: O = { b: '' }
->o : Symbol(o, Decl(indexedAccessRetainsIndexSignature.ts, 9, 5))
+export const o: O = { b: '' }
+>o : Symbol(o, Decl(indexedAccessRetainsIndexSignature.ts, 9, 12))
 >O : Symbol(O, Decl(indexedAccessRetainsIndexSignature.ts, 6, 67))
->b : Symbol(b, Decl(indexedAccessRetainsIndexSignature.ts, 9, 14))
+>b : Symbol(b, Decl(indexedAccessRetainsIndexSignature.ts, 9, 21))
 

tests/baselines/reference/indexedAccessRetainsIndexSignature.types

@@ -21,7 +21,7 @@ type O = Omit<{ a: number, b: string }, 'a'>
 >a : number
 >b : string
 
-const o: O = { b: '' }
+export const o: O = { b: '' }
 >o : Pick<{ a: number; b: string; }, "b">
 >{ b: '' } : { b: string; }
 >b : string

tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js

@@ -143,6 +143,8 @@ const Test1 = connect(
   null,
   mapDispatchToProps
 )(TestComponent);
+
+export {};
 
 
 //// [reactReduxLikeDeferredInferenceAllowsAssignment.js]
@@ -196,6 +198,7 @@ var __generator = (this && this.__generator) || function (thisArg, body) {
     }
 };
 var _this = this;
+exports.__esModule = true;
 var simpleAction = function (payload) { return ({
     type: "SIMPLE_ACTION",
     payload: payload

tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.symbols

@@ -469,3 +469,5 @@ const Test1 = connect(
 )(TestComponent);
 >TestComponent : Symbol(TestComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 134, 1))
 
+export {};
+

tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types

@@ -286,3 +286,5 @@ const Test1 = connect(
 )(TestComponent);
 >TestComponent : typeof TestComponent
 
+export {};
+

tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts

@@ -45,4 +45,6 @@ const myStoreConnect: Connect = function(
         mergeProps,
         options,
     );
-};
+};
+
+export {};

tests/cases/compiler/indexedAccessRetainsIndexSignature.ts

@@ -7,4 +7,4 @@ type Omit1<U, K extends keyof U> = Pick<U, Diff<keyof U, K>>;
 type Omit2<T, K extends keyof T> = {[P in Diff<keyof T, K>]: T[P]};
 
 type O = Omit<{ a: number, b: string }, 'a'>
-const o: O = { b: '' }
+export const o: O = { b: '' }

tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts

@@ -143,3 +143,5 @@ const Test1 = connect(
   null,
   mapDispatchToProps
 )(TestComponent);
+
+export {};