name.startsWith generate TS(2532)

Question

如果name是一个带有字符串"；test_ word"；

hWriteResult.lowest ? name === ('test_word')?  hWriteResult.lowest*2 : hWriteResult.lowest 

然后检查'test_word'

当我尝试使用：

hWriteResult.lowest ? name.startsWith === ('test')?  hWriteResult.lowest*2  : hWriteResult.lowest

我在name.startsWith === ('test')处得到一个错误。

(local var) name: string | undefined
Object is possibly 'undefined'.ts(2532)
This condition will always return 'false' since the types '(searchString: string, position?: number | undefined) => boolean' and 'string' have no overlap.ts(2367)

我怎样才能让它工作？

Answer 1

如果要测试name值startsWtih是否为值，请将其作为参数传递给startsWith()函数：

name.startsWith('test')

它将返回一个布尔值。

https://www.educative.io/answers/what-is-the-startswith-method-in-typescript