export function twoFer( arg : string ): string
{
if( arg !== "")
{
return "One for " arg ", one for me.";
}
return "One for you, one for me." ;
}
我無法理解我做錯了什么。在沒有提供引數的情況下，這是失敗的。
describe('TwoFer', () => {
it('no name given', () => {
const expected = 'One for you, one for me.'
expect(twoFer()).toEqual(expected)
})
})
輸出：
TEST FAILURE
Error: expect(received).toEqual(expected) // deep equality
Expected: "One for you, one for me."
Received: "One for undefined, one for me."
https://exercism.org/tracks/typescript/exercises/two-fer
uj5u.com熱心網友回復：
未指定的字串引數不包含空字串；它包含undefined. 你會想要這樣的東西：
export function twoFer(arg?: string): string
{
if(typeof arg !== "undefined") {
return "One for " arg ", one for me.";
}
return "One for you, one for me.";
}
更新：
或者，您可以arg使用默認值來代替引數以減少冗余。
export function twoFer(arg = "you"): string
{
return "One for " arg ", one for me.";
}
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/326548.html
標籤：javascript 打字稿