How to get element from component

Question

I Have some script, that takes element, but i cant find how to get it from react component. At least, i can get element after rendering, but now i have another problem - cant make event on button, coz i need SignatureObj

var SignaturePad = require('signature_pad');

var SignatureWidget = React.createClass({

    _handleClear: function(e, SignatureObj) {
        SignatureObj.clear();
    },

    _getSignature: function(canvas) {
        return new SignaturePad(canvas);
    },

    componentDidMount: function() {

        var wrapper = this.getDOMNode(),
            canvas  = wrapper.querySelector('canvas'),
            SignatureObj = this._getSignature(canvas);
    },

    render: function() {
        var canvas = React.createElement('canvas');

        return (
            <div>
                {canvas}
                <button>Clear</button>
            </div>
        );
    }
});

Finally, i need to get something like this

render: function() {
    var canvas = React.createElement('canvas'),
        >> canvasEl = canvas.getElement(),<< magic
        SignatureObj = this._getSignature(canvasEl);

    return (
        <div>
            {canvas}
            <button onClick={this._handleClear.bind(this, SignatureObj)}>Clear</button>
        </div>
    );
}

Answer 1

first some side notes, getDOMNode is deprecated, u should use findDOMNode, further u don't need to use create element within the render, because if you use the jsx syntax which u do it will be converted to the syntax u are using (createlement ..etc .. under the hood)

for your problem about selecting the element:

    React.findDOMNode(this.refs.findMe) 

<-- makes u find the node or as u call it :D (Magic)

    render: function() {
        return (
            <div>
                <canvas ref='findMe'></canvas> <------- magic
                <button>Clear</button>
            </div>
        );
    }

Hope this helps! some good reads:

refs: https://facebook.github.io/react/docs/more-about-refs.html

jsx: https://facebook.github.io/react/docs/jsx-in-depth.html

Answer 2

i used this way to add event

componentDidMount: function() {
    var pad             = this.refs.pad.getDOMNode(),
        saveButton      = this.refs.save.getDOMNode(),
        clearButton     = this.refs.clear.getDOMNode(),
        SignatureObj    = this._getSignature(pad);

    clearButton.onclick = this._handleClear.bind(this, SignatureObj);
    saveButton.onclick  = this._handleSave.bind(this, SignatureObj);
},