javascript - Angular Promise，为什么在这种情况下我会得到 'then' 的未定义？

Question

我的图表指令中有一个函数，它调用服务中的函数来获取数据，格式化该数据，然后从我的图表指令中调用另一个函数:

function chartTicker(ticker, disabled) {
    disabled = disabled || false;
    var defer = $q.defer();

    // Clear out previous chart:
    d3.selectAll("svg > *").remove();
    document.getElementById('chart').innerHTML = "";
    chart     = {},
    chartData = [];

    // Get and format data for chart:
    document.getElementById('chart').innerHTML = "<svg></svg>";
    var timeInHours = TimeSpanFactory.getTimeHours();

    var promise = FormatChartDataFactory.getData(ticker, timeInHours).then(function() {
        defer.resolve();
        return defer.promise;
    });
}

但是我在以下行中收到以下错误:

var promise = FormatChartDataFactory.getData(ticker, timeInHours).then(function() {

---

这是我的FormatChartDataFactory.getData函数:

function getData(ticker, limit) {
    var defer = $q.defer();
    chartObj.chartData = [{}];
    var limit_range = '';

    if (limit > 0) {
        limit_range = '?limit=' + limit;
    }

    getTickerPrice(ticker, limit_range).then(function() {
        defer.resolve();
        return defer.promise;
    });

    // GET Ticker data and return chartObj into drawChart:
    ////////////////////////////////////////////////////////////////////
    function getTickerPrice(ticker, limit_range) {
        return ApiFactory.getTickerQuotes(ticker.ticker, limit_range)
            .success(function(data, status, headers, config) {
                if (data.status === 'Success') {
                // ....

这是link to my full FormatChartDataFactory gist file .

Answer 1

Promise 应该直接从代码返回，而不应该从它的 .then 回调返回。简而言之，您尚未从函数返回 Promise，并且正在寻找 .then 方法，这会导致错误。

代码

//1st place
var promise = FormatChartDataFactory.getData(ticker, timeInHours).then(function() {
    defer.resolve();
});
return defer.promise;

//2nd place
getTickerPrice(ticker, limit_range).then(function() {
    defer.resolve();
});
return defer.promise;