流程和函數定義

Question

我試圖定義一個函數簽名在flow。我期望以下代碼拋出一個錯誤但我沒有得到任何錯誤呢？

// 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

看來流程確實發現您發佈的代碼有錯誤。

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