ARGV
In every NodeJS program, there is a magic array named argv.
It contains the command line arguments to the program.
If the user types this in the Terminal:
node hello.js Alice Bob
then process.argv contains:
[
'/usr/local/bin/node',
'/Users/alex/code/hello.js',
'Alice',
'Bob'
]
Why ARGV?
ARGV is a historical name. It means "Argument Vector" and has been around since the early 1970s.
LAB: Command-Line Hello
Write a new program called hi.js that contains:
console.log("Hi, " + process.argv[2] + "!")
and run it a few times from the Terminal, e.g.
node hi Alice
node hi Bob
node hi "good buddy"
LAB: Hi, Everybody!
Change hi.js to say hi to every one of its command line arguments.
For instance:
node hi Alice Bob Charlie
Hi, Alice!
Hi, Bob!
Hi, Charlie!
LAB: Add
Write a program named add.js that adds all of its command line arguments together.
e.g.
node add 1 2 3 4
10
Hint: Command line arguments come in as strings so you will need to convert them to numbers.
Add solution
Hint 1
```js
let numberArray = process.argv.slice(2).map(number => parseInt(number))
```
Hint 2
```js
let sum = 0
```
Solution
```js
let numbers = process.argv.slice(2);
function add(array){
let sum = 0
let intArray = numbers.map(number => parseInt(number))
intArray.forEach(int => sum += int)
return sum
}
console.log(add(numbers))
```