topic 1: assigning a function to a javascript object

• Javascript has some function programming features.
• Assign a function to a variable is one example.

        // procedure programming 
        function myFunction(p1,p2){
          return p1 + p2
        }
        var sum = myFunction(1, 2)
        console.log('1 + 2 = ' + sum)

        // function programming feature - assign a function to a javascript object
        var myVar = function(p1, p2){   //assign
          return p1 * p2
        }
        var product = myVar(2, 3)    //execute it
        console.log('2 * 3 = ' + product)

        // object programming feature
        // 1. javascript has new operator
        // 2. It is more involved. I'll not to create one.
        // 3. If you have to deal with some, find their usages and just use them.
            

topic 2: exports-require

        // -------     example 1  -------------------
        // part2.js
        module.exports = function(){
            console.log('hello world fromm part2.js')
        }

        // app2.js
        require('./part2.js')()   // execute the function
            
        // node app2.js     use and run the function at one name, a function name is not needed.
         
        // ----------------  example 2 ---------------  
        // with function arguments and return data 

        // part2x.js
        module.exports = function(p1){
            return p1 * p1
        };

        //  app2x.js
        var square = require('./part2x.js')
        var result = square(5)
        console.log('result = ' + result)     // 25