How to modify JSON array?

Question

How can I update a value at a specific index in the following multi dimensional JSON array?

I would like to update the value of background-image placed inside the footer_logo node.

{
    "Machine1": {
        "sidebar_inner": {
            "img": "img/pill.png",
            "background-color": "#ffffff",
            "side_logo": {
                "background-image": "../footer_logo.png"
            }
        },
        "lb_footer": {
            "img": "img/bin.png",
            "footer_logo": {
                "background-image": "..img/footer_logo.png"
            }
        },
        "machine_stand": {
            "img": "img/machine_stand.png"
        },
        "side": {
            "backgroundcolor": "#ccc"
        }
    }
}

Try to describe your question clearly, right now it is unclear and vague. — Gaurav Kalyan
– Gaurav Kalyan, Commented Dec 24, 2014 at 12:35
Being pedantic: This isn't a JSON array, it's a JS object, similar to a hash map in other languages. — caffeinated.tech
– caffeinated.tech, Commented Dec 24, 2014 at 12:40
@AyazShakoor, please see my answer for the background-image footer_logo. — Adam
– Adam, Commented Dec 24, 2014 at 12:47

Stefan Koenen · Accepted Answer · 2014-12-24 12:41:19Z

I've added a jsfiddle example here. It's prety simple, take a look at the code below.

var myJson = {
        "Machine1": {
            "sidebar_inner": {
                "img": "img/pill.png",
                "background-color": "#ffffff",
                "side_logo": {
                    "background-image": "../footer_logo.png"
                }
            },
            "lb_footer": {
                "img": "img/bin.png",
                "footer_logo": {
                    "background-image": "..img/footer_logo.png"
                }
            },
            "machine_stand": {
                "img": "img/machine_stand.png"
            },
            "side": {
                "backgroundcolor": "#ccc"
            }
        }
    };

    myJson.Machine1.lb_footer.footer_logo['background-image'] = 'New value.';

    alert(myJson.Machine1.lb_footer.footer_logo['background-image']);

Adam · Accepted Answer · 2014-12-24 12:43:46Z

To update nested values, you would chain keys (indexes are for arrays) together to find the appropriate value.

Here's the code, formatted for easy consumption:

var obj = {"Machine1": {
    "sidebar_inner": {
        "img": "img/pill.png",
        "background-color": "#ffffff",
        "side_logo": {
            "background-image": "../footer_logo.png"
        }
    },
    "lb_footer": {
        "img": "img/bin.png",
        "footer_logo": {
            "background-image": "..img/footer_logo.png"
        }
    },
    "machine_stand": { 
        "img": "img/machine_stand.png"
    }, 
    "side": {
        "backgroundcolor":"#ccc"
    }
}}

Examples

To update "footer_logo"'s background image: obj.Machine1.lb_footer,footer_logo.background-image = "something new";

To update "machine_stand's" img:

obj.machine_stand.img = "new/link.jpg";
// or use 'bracket notation', it's the same thing
obj['machine_stand']['img'] = "new/link.jpg"

vaso123 · Accepted Answer · 2014-12-24 12:42:27Z

1

Try this. A working jsfiddle

    var json= '{"Machine1":{"sidebar_inner":{"img":"img\/pill.png","background-color":"#ffffff","side_logo":{"background-image":"..\/footer_logo.png"}},"lb_footer":{"img":"img\/bin.png","footer_logo":{"background-image":"..img\/footer_logo.png"}},"machine_stand":{"img":"img\/machine_stand.png"},"side":{"backgroundcolor":"#ccc"}}}';
    var jsonObj = JSON.parse(json);
    jsonObj.Machine1.lb_footer.footer_logo['background-image'] = 'abc';

answered Dec 24, 2014 at 12:42

vaso123

12.4k4 gold badges37 silver badges68 bronze badges

4 Comments

Roy Dictus Over a year ago

Why put the data first in a string and then parse it?

vaso123 Over a year ago

Do not understand. First, for demonstration, second, if you do not parse it, you can not access it as an object. Or do you meant, why not inject it directly in the parse the string?

Roy Dictus Over a year ago

I don't know what you mean by directly in the parse the string. But you could omit the quotes and then you don't need to parse. Sew the other answers.

vaso123 Over a year ago

Oh, I see. I do it, because I was not sure, is this coming from an AJAX, or is this in javascript. I've just want to demonstrate, what if it is a string.

NatureShade · Accepted Answer · 2014-12-24 12:47:00Z

0

arr["Machine1"]["lb_footer"]["footer_logo"]["background-image"] = mynewvalue;

edited Dec 24, 2014 at 12:47

answered Dec 24, 2014 at 12:41

NatureShade

2,2671 gold badge21 silver badges27 bronze badges

1 Comment

vaso123 Over a year ago

lb_footer is twice, and no footer_logo

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