Declaring Functions
Functions allow you to package up lines of code that you can use (and often reuse) in your programs.
function reversString(reverseMe) {
var reversed = "";
for (var i = reverseMe.length - 1; i >= 0; i--) {
reversed += reverseMe[i];
}
return reversed;
}
The reverseString() function had one parameter: the string to be reversed. In both cases, the parameter is listed as a variable after the function name, inside the parentheses. And, if there were multiple parameters, you would just separate them with commas.
Return statements
function sayHello() {
var message = "Hello!"
console.log(message);
}
In the sayHello() function above, a value is printed to the console with console.log, but not explicitly returned with a return statement.
You can write a return statement by using the return keyword followed by the expression or value that you want to return.
function sayHello() {
var message = "Hello!"
return message; // returns value instead of printing it
}
Function Recap
Functions package up code so you can easily use (and reuse) a block of code.
Parameters are variables that are used to store the data that's passed into a function for the function to use.
Arguments are the actual data that's passed into a function when it is invoked:
function add(x, y) {
var sum = x + y;
return sum; // return statement
}
Code Snippets
for(var i=0; i<numbers.length; i++){
for(var j=0; j<numbers[i].length; j++){
if(numbers[i][j]%2===0)
numbers[i][j]="even";
else
numbers[i][j]="odd";
}
}
console.log(numbers);
var facebookProfile = {
name: "Bear",
friends: 123,
messages: ["Bear loves fish", "Bear loves nap", "Bear love honey"],
postMessage: function(message) {
facebookProfile.messages.push(message);
},
deleteMessage: function(index) {
facebookProfile.messages.splice(index, 1);
},
addFriend: function() {
facebookProfile.friends = facebookProfile.friends + 1;
},
removeFriend: function() {
if(facebookProfile.friends >0)
facebookProfile.friends = facebookProfile.friends - 1;
}
};
console.log(facebookProfile);
Summary
Happy Hacking!!!
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