Why symbol :: is needed in onClick={::this.handleToggleKitten} ?

[whatifif]

I know that symbol :: is used to call a static method in PHP language.

I see this symbol is used in source code of this react-redux-universal-hot-example like below in "About Us" page:
onClick={::this.handleToggleKitten}

Why this should not be onClick={this.handleToggleKitten} without symbol :: ?

Thanks in advance

[isilweo]

this is function bind operator, it does not work like :: in PHP. You can read about it on link below
http://babeljs.io/blog/2015/05/14/function-bind/ or https://github.com/zenparsing/es-function-bind
It is proposed for ES7 and is currently on stage 0.

{::this.handleToggleKitten} is equivalent of this.handleToggleKitten.bind(this)

It was also removed from source code on this repo with PR #547

[whatifif]

Thanks for your kind explanation.

I think that using the arrow function is a better way than using this new symbol :: for this purpose.