流程和函数定义

Question

我试图定义一个函数签名在flow。我期望以下代码抛出一个错误但我没有得到任何错误呢？

// function that applied a function to an array - just for numbers 
const arrayMath = (func:() => number, arr: Array<number>):Array<Number> => arr.map(func); 

// would expect this function to work OK with arrayMath 
const square = (num: number): number => num * num; 

// would expect this function to fail with arrayMath 
const concatX = (str: string): string => `${str}X`; 

// flow is not giving me an error here.. 
arrayMath(concatX, [1, 2, 3]); 

Answer 1

看来流程确实发现您发布的代码有错误。

https://flow.org/try/#0PTAEAEDMBsHsHcBQiSkgVwHYGMAuBLWTUXACwENdRyAHG6fAUwBNq0s9DjdZrjyATgPIBPUAFpQAK3QBnKpFgDQmdAFsARowGzE2IvOpDRAWUqlQAXlAAKDDgBctgJRWAfCvVaBAGiMCnAEFjEQAeVU1tN2cHYOEwgDkvKPd-ADo1WjsOZwBuZFR4WHRoVkYADxpGPBJSfFl2HAIiEl4igQBrUAB5AGlQeHwyf1NzPQMqWQBHdEFGK1sIpwjvGM9I5UsPCNAAKnX8lDAikrLK6qoyesbOFp40cnxoAaGLQXizMnHMQ30cSgAGgsbPIAqBQfhMABzNYQ6GpAAGABIAN6ggC+AIRh1QMAQoGumFgVCh+AAbpCoaA1PNyMRtAIlKBSNpGGk0oh3qMyDY-thAX4ANoARj8ACY-ABmAC6eSAA