//// [contextualTypeWithUnionTypeCallSignatures.ts] //When used as a contextual type, a union type U has those members that are present in any of // its constituent types, with types that are unions of the respective members in the constituent types. // Let S be the set of types in U that have call signatures. // If S is not empty and the sets of call signatures of the types in S are identical ignoring return types, // U has the same set of call signatures, but with return types that are unions of the return types of the respective call signatures from each type in S. interface IWithNoCallSignatures { foo: string; } interface IWithCallSignatures { (a: number): string; } interface IWithCallSignatures2 { (a: number): number; } interface IWithCallSignatures3 { (b: string): number; } interface IWithCallSignatures4 { (a: number): string; (a: string, b: number): number; } // With no call signature | callSignatures var x: IWithNoCallSignatures | IWithCallSignatures = a => a.toString(); // With call signatures with different return type var x2: IWithCallSignatures | IWithCallSignatures2 = a => a.toString(); // Like iWithCallSignatures var x2: IWithCallSignatures | IWithCallSignatures2 = a => a; // Like iWithCallSignatures2 // With call signatures of mismatching parameter type var x3: IWithCallSignatures | IWithCallSignatures3 = a => /*here a should be any*/ a.toString(); // With call signature count mismatch var x4: IWithCallSignatures | IWithCallSignatures4 = a => /*here a should be any*/ a.toString(); //// [contextualTypeWithUnionTypeCallSignatures.js] //When used as a contextual type, a union type U has those members that are present in any of // its constituent types, with types that are unions of the respective members in the constituent types. // With no call signature | callSignatures var x = function (a) { return a.toString(); }; // With call signatures with different return type var x2 = function (a) { return a.toString(); }; // Like iWithCallSignatures var x2 = function (a) { return a; }; // Like iWithCallSignatures2 // With call signatures of mismatching parameter type var x3 = function (a) { return a.toString(); }; // With call signature count mismatch var x4 = function (a) { return a.toString(); };