Blockly is a ROS package that provides web-based visualization and block programming tools for robots and drones.
Simply join the laser block and a variable to read the laser. To use that same variable as many times as needed, "duplicate" option must be selected when right clicking that variable-block.
Laser block reads the value from the corresponding ros-topic and saves it in the variable attached to the block. No initialization block is needed as this same block launched the new node.
Full example using a Erle-Spider can be found here.