assert-is-function-x
If isFunction(callbackfn) is false, throw a TypeError exception.
module.exports(callback)
⇒ *
⏏
Tests callback
to see if it is a function, throws a TypeError
if it is
not. Otherwise returns the callback
.
Kind: Exported function
Returns: *
- Returns callback
if it is function.
Throws:
TypeError
Throws ifcallback
is not a function.
Param | Type | Description |
---|---|---|
callback | * |
The argument to be tested. |
[message] | string |
Optional alternative message. |
Example
import assertIsFunction from 'assert-is-function-x';
const primitive = true;
const mySymbol = Symbol('mySymbol');
const symObj = Object(mySymbol);
const object = {};
const fn = function fn() {};
assertIsFunction(primitive); // TypeError 'true is not a function'.
assertIsFunction(object); // TypeError '#<Object> is not a function'.
assertIsFunction(mySymbol); // TypeError 'Symbol(mySymbol) is not a function'.
assertIsFunction(symObj); // TypeError '#<Object> is not a function'.
console.log(assertIsFunction(fn)); // Returns fn.