Question

运行我的JavaScript时，它将调用getDoctorComplete函数。 AJAX请求完成后，它将设置a = chelsea。否则，将进行触发器更改并运行$('#dropdown_hosp').change(...。在$('#dropdown_hosp').change(...中，它将调用getSpecialty函数。使用getSpecialty函数完成AJAX请求后，我想获取a的值。我console.log，但其中包含一个空字符串。我该如何解决这个问题？

var a = '';
$(document).ready(function () {
    app.getHospital({
        areaId: ''
    });

    app.getDoctorComplete({
        doctorId: doctorId,
        doctorel: $('#dropdown_doct')
    });

    $('#dropdown_hosp').change(function () {
        var dropdownspecialty = $('#dropdown_spec');
        app.getSpecialty({
            hospitalId: $('#dropdown_hosp').val(),
            apiUrl: 'api',
            special: dropdownSpec
        });
    });
});

app = function () {
    function getHospital({
        areaId
    }) {
        // ...
        $.ajax({
            // ...
            success: function (result) {
                // ...
            },
            // ...
        }).done(function () {
            $('#dropdown_hosp').select2();
        });
    };

    function getSpecialty({
        hospitalId,
        apiUrl,
        special
    }) {
        // ...
        $.ajax({
            // ...
        }).done(function () {
            // test here
            console.log(a);
        });
    };

    function getDoctorComplete({
        schdoctor_id,
        doctorel
    }) {
        // ...
        $.ajax({
            // ...
            success: function (result) {
                // ...
            },
            // ...
        }).done(function () {
            // ...
            a = 'chelsea';
            b = '..';
            $('#dropdown_hosp').val(b).trigger('change');
        });
    };
    return {
        getSpecialty: getSpecialty,
        getDoctorComplete: getDoctorComplete
    }
}();

Answer 1

您的问题在于，您的ajax呼叫是异步的，因此a在登录时不会重新分配。这将是使用Promise，创建异步函数resolve，标记该异步函数的return和.then()之后执行某些操作的解决方案异步功能：

var a = '';
$(document).ready(function () {
    app.getHospital({
        areaId: ''
    });

    app.getDoctorComplete({
        doctorId: doctorId,
        doctorel: $('#dropdown_doct')
    })
        .then(() => { // Add the .then() callback to do something after getDoctorComplete finished
            $('#dropdown_hosp').change(function () {
                var dropdownspecialty = $('#dropdown_spec');
                app.getSpecialty({
                    hospitalId: $('#dropdown_hosp').val(),
                    apiUrl: 'api',
                    special: dropdownSpec
                });
            });
        });
});

app = function () {
    function getHospital({
        areaId
    }) {
        return new Promise((resolve, reject) => {
            // ...
            $.ajax({
                // ...
                success: function (result) {
                    // ...
                },
                // ...
            }).done(function () {
                $('#dropdown_hosp').select2();

                resolve(); // Add resolve
            });
        });
    };

    function getSpecialty({
        hospitalId,
        apiUrl,
        special
    }) {
        return new Promise((resolve, reject) => {
            // ...
            $.ajax({
                // ...
            }).done(function () {
                // test here
                console.log(a);

                resolve(); // Add resolve
            });
        });
    };

    function getDoctorComplete({
        schdoctor_id,
        doctorel
    }) {
        return new Promise((resolve, reject) => {
            // ...
            $.ajax({
                // ...
                success: function (result) {
                    // ...
                },
                // ...
            }).done(function () {
                // ...
                a = 'chelsea';
                b = '..';
                $('#dropdown_hosp').val(b).trigger('change');

                resolve(); // Add resolve
            });
        });
    };
    return {
        getSpecialty: getSpecialty,
        getDoctorComplete: getDoctorComplete
    }
}();

触发时如何传递参数？

1 个答案: