A wonderful tool which converts expressions in infix notation to postfix notation using recursion.
npm install infix-to-postfix-notation``
npm install --save infix-to-postfix-notation
`JavaScript``
var PostfixNotationConverter = require("infix-to-postfix-notation");
PostfixNotationConverter.convertToPostfixNotation("((1(2+3))/4)"); // 123+4/
##### Enjoy!