Simple JSON viewer

index.pug

 
.target

script.js

function jsonViewer(json, collapsible=false) {
    var TEMPLATES = {
        item: '<div class="json__item"><div class="json__key">%KEY%</div><div class="json__value json__value--%TYPE%">%VALUE%</div></div>',
        itemCollapsible: '<label class="json__item json__item--collapsible"><input type="checkbox" class="json__toggle"/><div class="json__key">%KEY%</div><div class="json__value json__value--type-%TYPE%">%VALUE%</div>%CHILDREN%</label>',
        itemCollapsibleOpen: '<label class="json__item json__item--collapsible"><input type="checkbox" checked class="json__toggle"/><div class="json__key">%KEY%</div><div class="json__value json__value--type-%TYPE%">%VALUE%</div>%CHILDREN%</label>'
    };

    function createItem(key, value, type){
        var element = TEMPLATES.item.replace('%KEY%', key);

        if(type == 'string') {
            element = element.replace('%VALUE%', '"' + value + '"');
        } else {
            element = element.replace('%VALUE%', value);
        }

        element = element.replace('%TYPE%', type);

        return element;
    }

    function createCollapsibleItem(key, value, type, children){
        var tpl = 'itemCollapsible';
        
        if(collapsible) {
            tpl = 'itemCollapsibleOpen';
        }
        
        var element = TEMPLATES[tpl].replace('%KEY%', key);

        element = element.replace('%VALUE%', type);
        element = element.replace('%TYPE%', type);
        element = element.replace('%CHILDREN%', children);

        return element;
    }

    function handleChildren(key, value, type) {
        var html = '';

        for(var item in value) { 
            var _key = item,
                _val = value[item];

            html += handleItem(_key, _val);
        }

        return createCollapsibleItem(key, value, type, html);
    }

    function handleItem(key, value) {
        var type = typeof value;

        if(typeof value === 'object') {        
            return handleChildren(key, value, type);
        }

        return createItem(key, value, type);
    }

    function parseObject(obj) {
        _result = '<div class="json">';

        for(var item in obj) { 
            var key = item,
                value = obj[item];

            _result += handleItem(key, value);
        }

        _result += '</div>';

        return _result;
    }
    
    return parseObject(json);
};



var json = {
    'User' : {
        'Personal Info': {
            'Name': 'Eddy',
            'Age': 3
        },
        'Active': true,
        'Messages': [
            'Message 1',
            'Message 2',
            'Message 3'
        ]
    },
    'Total': 1
}

var el = document.querySelector('.target');
el.innerHTML = jsonViewer(json, true);

simple-json-viewer.markdown

Simple JSON viewer

A simple JSON viewer written. Collapsing is done with pure CSS. JS is only used to parse the JSON and generate the HTML accordingly.

A Pen by Wart Claes on CodePen.

License.

style.scss

@import url('https://fonts.googleapis.com/css?family=Source+Code+Pro');

.json {
    font-family: 'Source Code Pro', monospace;
    font-size: 16px;
    
    & > {
        .json__item {
            display: block;
        }
    }
}

.json__item {
    display: none;
    margin-top: 10px;
    padding-left: 20px;
    user-select: none;
}

.json__item--collapsible {
    cursor: pointer;
    overflow: hidden;
    position: relative;
    
    &::before {
        content: '+';
        position: absolute;
        left: 5px;
    }
    
    &::after {
        background-color: lightgrey;
        content: '';
        height: 100%;
        left: 9px;
        position: absolute;
        top: 26px;
        width: 1px;
    }
    
    &:hover {
        & > .json__key,
        & > .json__value {
            text-decoration: underline;
        }
    }
}

.json__toggle {
    display: none;
    
    &:checked ~ .json__item {
        display: block;
    }
}

.json__key {
    color: darkblue;
    display: inline;
    
    &::after {
        content: ': ';
    }
}

.json__value {
    display: inline;
}

.json__value--string {
    color: green;
}

.json__value--number {
    color: blue;
}

.json__value--boolean {
    color: red;
}

I made a similar app as well: https://simple.tools/json-viewer. It helps you view and understand your JSON data in a very simple and clean way. The goal was to make it easy to quickly inspect JSON structures without unnecessary complexity, especially when you just want to paste your data and instantly see a formatted, readable result. It’s a lightweight tool, but quite handy for developers who work with JSON frequently.