src/courier/PostMessageChannel.js
function _isHandshake(event) {
            return (event && event.data && "string" === typeof event.data && (0 === event.data.indexOf(TOKEN_PREFIX) || (HANSHAKE_PREFIX + this.token) === event.data));
        }
function _isHandshake(event) {
            return (event && event.data && "string" === typeof event.data && (0 === event.data.indexOf(TOKEN_PREFIX) || (HANSHAKE_PREFIX + this.token) === event.data));
        }
function _isHandshake ( event ) { return ( event && event . data && "string" === typeof event . data && ( 0 === event . data . indexOf ( TOKEN_PREFIX ) || ( HANSHAKE_PREFIX + this . token ) === event . data ) ) ; }
Method to validate whether an event is for handshake
@param {Object} event - the event object on message
@private
Method to validate whether an event is for handshake