gun set if unique (Working)

setu.js

function setu(node, item){
        let unique = true
        node.map().once(function (data) {
            let aProps = Object.getOwnPropertyNames(data);
            let bProps = Object.getOwnPropertyNames(item);
            // number of properties
            if ((aProps.length-1) === bProps.length) {
                for (let i = 1; i < aProps.length; i++) {
                    let propName = aProps[i];
                    // values of same property
                    if (data[propName] === item[propName]) {
                        unique = false
                    }
                }
            }
        })
        .then(function(){
            if(unique){
                node.set(item)
            }
        })
    }