javascript - The function return value needs to be processed by the callback function of the internal method. How to write it?

Question

For example {code...} I need to get the processed b. How should I change this function?

習慣沉默 · Answer

The result of the callback function can only be sent out using the callback function.

function a(a,b,callback){
    $.messager.confirm('xxx','xx',function(r){
        if(r){
            b = 1;
        }else{
            b = 2;
        }
        callback(b)
    });
}

曾经蜡笔没有小新 · Answer

Look at the form$.messager.confirm is an asynchronous call, you can wrap this call with a layer of promise;

function a(a,b) {
    return new Promise(function(resolve, reject) {
        $.messager.confirm('xxx','xx',function(r){
            if (r) {
                b = 1;
            } else{
                b = 2;
            }
            resolve(b);
        });
    });
}

When calling a, you can call it as follows

a(xxx, xxx).then(function(b) {
    // b就是上面resolve的值
});

PHP中文网 · Answer

function a(a,b){
    let t;
    $.messager.confirm('xxx','xx',function(r){
        if(r){
            t = 1;
        }else{
            t = 2;
        }
    });
    return t;
}

//或者
function a(a,b){
    $.messager.confirm('xxx','xx',function(r){
        if(r){
            return  1;
        }else{
            return  2;
        }
    });
}

三叔 · Answer

The callback function is executed after your main function is executed, which means that you must first have two parameters, xxx and xx, and then the callback is executed. There is nothing wrong with your function.