I have two js files add.js and testAdd.js
module.exports = function add(x,y) {
console.log("------Starts x+y----");
var a = x+y;
console.log(a);
return a;
}
module.exports = function add(x,y,z) {
console.log("------Starts x+y+z----");
var a = x+y+z;
console.log(a);
return a;
}
var add = require('./add');
add(300,100);
add(300,100,233);
From the testAdd I am calling the add method in the add.js
What is happening is function call is always going to the add(x,y,z) as function is not selecting based on the parameters(as in java).
I am new to nodeJS. Can someone help me to understand this flow? And also help me to fix this issue. Thanks in advance.
Attaching the console o/p:-
JavaScript doesn't have function overloading. If you want to have your function take an optional third argument, you can set a default value (with a recent Node version):
function add(x, y, z = 0) {
...
}
You can use it with two ( add(300, 100)
) or with three ( add(300, 100, 233)
) arguments.
If you don't have a recent enough Node version, you have to do some manual validation on the third argument:
function add(x, y, z) {
z = Number.isFinite(z) ? z : 0;
...
}
Javascript does not support function overloading. Although robertklep 's solution is great. There is one more way you can use.That is arguments object .
arguments is very good when you have unknown number of parameters to be passed into the function. see more here .
Below is how will it look.
//add.js
function add() {
var args=Array.prototype.slice.call(arguments);
console.log(arguments);
console.log(args);
console.log("------Starts x+y+z+.....and so on----");
var ans = args.reduce(function(prev,curr){return prev+curr;});
console.log(ans);
return ans;
}
var sum = add(1,8,32,4);
module.exports = add;//to make it available outside.
On executing the above.(as node add.js
),The output is as follows.
{ '0': 1, '1': 8, '2': 32, '3': 4 }
[ 1, 8, 32, 4 ]
------Starts x+y+z+.....and so on----
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