if (typeof myFunction !== 'function') – why doesn't it work in Safari?

Question

I have this code that works in Chrome, but doesn't work as expected in Safari:

if (typeof myFunction !== 'function') {

  function myFunction() {
    console.log('myFunction invoked');
  }

  myFunction();

} else {
  console.log('myFunction ALREADY DEFINED o_O!');
}

When I run this code in Chrome – it logs "myFunction invoked".

When I run it in Safari – it logs "myFunction ALREADY DEFINED o_O!"

I want to make typeof work in Safari the same as in Chrome. How can I achieve it?

Probably due to [hoisting](https://developer.mozilla.org/en-US/docs/Glossary/Hoisting) — p.s.w.g, Apr 23 '19 at 21:57
Putting a `function` declaration statement in an `if` block is bad practice and not allowed in "strict" mode. The behavior was basically undefined. — Pointy, Apr 23 '19 at 22:01
did you test this : `if (typeof(myFunction) !== 'function' ) { ...` or`if (typeof(myFunction) === 'undefined' ) { ...` — Mister Jojo, Apr 23 '19 at 22:03
Which is a best practice for when I need to define a function inside a template that can be included multiple times inside the code? — Dmitrii Kuznetsov, Apr 23 '19 at 22:30

score 0 · Accepted Answer · answered Apr 23 '19 at 22:00

0

just use the below code :

if (typeof myFunction !== 'function') {

  let myFunction = function() {
    console.log('myFunction invoked');
  }

  myFunction();

} else {
  console.log('myFunction ALREADY DEFINED o_O!');
}

let keyword will fix your problem

answered Apr 23 '19 at 22:00

Milad Bonakdar

273
2
16

Yay! This one worked for me. – Dmitrii Kuznetsov Apr 23 '19 at 22:33

if (typeof myFunction !== 'function') – why doesn't it work in Safari?

1 Answers1