SOURCE

const json = {
    "tag": "div",
    "props":{
        "className":"container"
    },
    "children":[
        {
            "tag":"h1",
            "children":["Hello world"]
        },
        {
            "tag":"p",
            "props":{
                "style":{
                    "color":"blue"
                }
            },
            "children":["This is a paragraph"]
        }
    ]
}

function jsonToJSX(json) {
    if(!json.tag) return null;

    const props = json.props || {};
    const children = json.children 
    ? json.children.map(child =>
    typeof child === 'string' ? child : jsonToJSX(child))
    :null;
    return React.creatElement(jon.tag,props,children);
}