javascript - 如何以编程方式链接两个js函数？

Question

我正在尝试解决如何链接多个 js 函数(本例中为两个)。我有一个 JavaScript 函数用于 save()，另一个用于 saveAndPrint()。我需要链接该调用，因为我需要在 save() 中生成的 id 来转发它以便在第二个调用中进行打印。也许我只能使用一个函数来完成这两件事，但我想学习如何做到这一点。目前我只是得到一个“未定义”，因为第二个函数在第一个函数完成之前启动。 这是代码:

$scope.save = function () {
    var receipt = {
        documentType: 'RCI',
        expirationDate: new moment().format('YYYY-MM-DD'),
        person: {id: $scope.financeDocuments[0].person.id},
        payments: getPayments(),
        promotions: [],
        creationDate: new moment().format('YYYY-MM-DD'),
        compensatedDocuments: getDocumentsToPay()
    };

    financeDocumentService.save(receipt, function (response) {
        receipt = response;
        $uibModalInstance.close(response);
    }).$promise.then(function (data) {
        return receipt;
    });
};

$scope.saveAndPrint = function() {
    var document = $scope.save();                    
        $window.location.href = "#/finance/receipt_show/"+document.id;
};

非常感谢!

Answer 1

首先返回 promise :

$scope.save = function () {
    var receipt = {
        documentType: 'RCI',
        expirationDate: new moment().format('YYYY-MM-DD'),
        person: {id: $scope.financeDocuments[0].person.id},
        payments: getPayments(),
        promotions: [],
        creationDate: new moment().format('YYYY-MM-DD'),
        compensatedDocuments: getDocumentsToPay()
    };

    //RETURN the promise
    ͟r͟e͟t͟u͟r͟n͟  financeDocumentService.save(receipt, function (response) {
        receipt = response;
        $uibModalInstance.close(response);
    }).$promise.then(function (data) {
        return receipt;
    });
};

然后从 promise 中链接:

$scope.saveAndPrint = function() {
    var promise = $scope.save();     
    promise.then(function(receipt) {                    
        $window.location.href = "#/finance/receipt_show/"+document.id;
    });
};

欲了解更多信息，

• AngularJS $q Service API Reference - Chaining Promises
• You`re Missing the Point of Promises