How to update nodejs

npm cache clean -f
sudo npm install -g n
sudo n stable

npm install npm@latest -g

how to download php composer

php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"
php -r "if (hash_file('SHA384', 'composer-setup.php') === '544e09ee996cdf60ece3804abc52599c22b1f40f4323403c44d44fdfdd586475ca9813a858088ffbc1f233e9b180f061') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"
php composer-setup.php
php -r "unlink('composer-setup.php');"

Install Tex2PNG on system

use below commands:

sudo apt-get install texlive-latex-base (for latex command)

install dvipng

use Tex2Png php library

https://github.com/Gregwar/Tex2png/blob/master/Tex2png.php