CODEWITHSUNDEEP
javascriptarraysfunction
Aido
Aido

Reputation: 1584

Return array from function

--Solved by Elliot B. Thanks! May also take into account the other modifications.

Here is the result. Thanks, everyone, for the speedy answers! http://dl.dropbox.com/u/18785762/Rust/index.html

I'm writing a game in javascript, and I want to keep the files for matching block IDs to files in a seperate .js file from the map compiler, so that I can edit things easily. However, the IDs are stored in an array, and I can't seem to get it to use the return function properly. Any help?

drawmap.js:

function drawmap() {
    
    var images = BlockID();
    
    var level = [
    "ssssssssssssssssssssss",
    "sgggggggggCCCCCdddddss",
    "ssssssssss     sssssss"
    ];

    var top = 100;
    var left = 100;
    var mytop = top;
    var myleft = left;
    for (y=0; y<level.length; ++y) {
        var row = level[y];
        for (x=0; x < row.length; ++x) {
            var c = row.charAt(x);
            if(c != ' ') {
                img_create(images[c], mytop, myleft);
            }
            mytop += 13;
            myleft += 27;
        }
        mytop = top + (y+1)*13;
        myleft = left - (y+1)*27;
    }
}

mapread.js:

function BlockID() {
    var IDs = new Array();
        images['s'] = "Images/Block_01.png";
        images['g'] = "Images/Block_02.png";
        images['C'] = "Images/Block_03.png";
        images['d'] = "Images/Block_04.png";
    return IDs;
}

Upvotes: 36

Views: 417588

Answers (4)

ognyanz
ognyanz

Reputation: 9

Taking in consideration that in JavaScript Array is object too this can be written as:

function BlockID() {
    return new Array(
        "Images/Block_01.png", 
        "Images/Block_02.png", 
        "Images/Block_03.png", 
        "Images/Block_04.png" 
       );
    }

This code will display content of array in browser's window

window.onload=function(){
var s="";
var ar = BlockID(); //function return array
for(el in ar){
    s+=ar[el]+"</br>";
}
document.body.innerHTML=s; 
};

Upvotes: 0

Elliot B.
Elliot B.

Reputation: 17661

At a minimum, change this:

function BlockID() {
    var IDs = new Array();
        images['s'] = "Images/Block_01.png";
        images['g'] = "Images/Block_02.png";
        images['C'] = "Images/Block_03.png";
        images['d'] = "Images/Block_04.png";
    return IDs;
}

To this:

function BlockID() {
    var IDs = new Object();
        IDs['s'] = "Images/Block_01.png";
        IDs['g'] = "Images/Block_02.png";
        IDs['C'] = "Images/Block_03.png";
        IDs['d'] = "Images/Block_04.png";
    return IDs;
}

There are a couple fixes to point out. First, images is not defined in your original function, so assigning property values to it will throw an error. We correct that by changing images to IDs. Second, you want to return an Object, not an Array. An object can be assigned property values akin to an associative array or hash -- an array cannot. So we change the declaration of var IDs = new Array(); to var IDs = new Object();.

After those changes your code will run fine, but it can be simplified further. You can use shorthand notation (i.e., object literal property value shorthand) to create the object and return it immediately:

function BlockID() {
    return {
            "s":"Images/Block_01.png"
            ,"g":"Images/Block_02.png"
            ,"C":"Images/Block_03.png"
            ,"d":"Images/Block_04.png"
    };
}

Upvotes: 50

Bergi
Bergi

Reputation: 664538

Your BlockID function uses the undefined variable images, which will lead to an error. Also, you should not use an Array here - JavaScripts key-value-maps are plain objects:

function BlockID() {
    return {
        "s": "Images/Block_01.png",
        "g": "Images/Block_02.png",
        "C": "Images/Block_03.png",
        "d": "Images/Block_04.png"
    };
}

Upvotes: 15

mplungjan
mplungjan

Reputation: 177940

neater:

function BlockID() {
  return {
    "s":"Images/Block_01.png",
    "g":"Images/Block_02.png",
    "C":"Images/Block_03.png",
    "d":"Images/Block_04.png"
   }
}

or just

var images = {
  "s":"Images/Block_01.png",
  "g":"Images/Block_02.png",
  "C":"Images/Block_03.png",
  "d":"Images/Block_04.png"
}

Upvotes: 8

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