19 lines
645 B
JavaScript
19 lines
645 B
JavaScript
//// [optionalFunctionArgAssignability.ts]
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interface Promise<T> {
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then<U>(onFulfill?: (value: T) => U, onReject?: (reason: any) => U): Promise<U>;
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}
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var a = function then<U>(onFulfill?: (value: string) => U, onReject?: (reason: any) => U): Promise<U> { return null };
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var b = function then<U>(onFulFill?: (value: number) => U, onReject?: (reason: any) => U): Promise<U> { return null };
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a = b; // error because number is not assignable to string
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//// [optionalFunctionArgAssignability.js]
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var a = function then(onFulfill, onReject) {
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return null;
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};
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var b = function then(onFulFill, onReject) {
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return null;
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};
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a = b;
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