has-callback

hasCallback

Check if function takes callback as argument.

Will check for common callback names in argument footprint:

• callback
• cb
• done
• next

API

hasCallback(fn, [userDefinedNames])

fn

Type: function

(Required)

The function to be tested.

userDefinedNames

Type: string | array

User-defined callback name string or list of strings.

Example Usage

import hasCallback from 'has-callback';

hasCallback(JSON.stringify);
// => false

hasCallback(fs.rename);
// => true

Limitations

This function merely checks the name of function arguments, it is not a reliable way of checking if a function is asynchronous, for example it will not detect if a function returns a Promise.