Yes! One more package detecting that given variable is function.
Made as drop-in replacement for is-callable package, but lighter and faster

Install it via npm or yarn

``bash
npm install is-fun


or via yarn

`javascript
const isFun = require("is-fun");

isFun(() => {}); // true
`

`typescript
import isFun from "is-fun";

isFun(undefined); // false
isFun(null); // false
isFun(false); // false
isFun(true); // false
isFun([]); // false
isFun({}); // false
isFun(/a/g); // false
isFun(new RegExp("a", "g")); // false
isFun(new Date()); // false
isFun(42); // false
isFun(NaN); // false
isFun(Infinity); // false
isFun(new Number(42)); // false
isFun("foo"); // false
isFun(Object("foo")); // false

isFun(function() {}); // true
isFun(function*() {}); // true
isFun(x => x * x); // true
`

Performance (recent benchmarks results)

benchmarks ran on 3.4GHz Core i7 CPU width 16GB DDR4 RAM

`bash
npm run build && npm i -C benchmark && npm -C benchmark start
``

Regular function

is-callable   × 3,679,405 ops/sec; (result: "true")
is-fun        × 6,736,726 ops/sec; (result: "true")
Fake function

is-callable   × 45,630 ops/sec; (result: "false")
is-fun        × 112,172 ops/sec; (result: "false")
Typed array constructor

is-callable   × 1,692,920 ops/sec; (result: "true")
is-fun        × 2,716,742 ops/sec; (result: "true")
Class constructor

is-callable   × 7,058,944 ops/sec; (result: "false")
is-fun        × 7,109,810 ops/sec; (result: "false")
Arrow function

is-callable   × 95,493,127 ops/sec; (result: "true")
is-fun        × 89,843,495 ops/sec; (result: "true")
Null

is-callable   × 124,068,441 ops/sec; (result: "false")
is-fun        × 126,135,930 ops/sec; (result: "false")
Number

is-callable   × 863,066,938 ops/sec; (result: "false")
is-fun        × 863,418,881 ops/sec; (result: "false")