将打字稿函数保存为对象变量(Angular 6)

Question

我正在尝试使用Google图表创建一个简单的抽象，我创建了一个图表服务，它将用作抽象。模块提供选项和数据源，服务负责其余部分(数据由 REST API 提供(。

这是当前的代码，仅适用于一种情况：

createCombo(comboBarLabels: String[], comboBarTypes: String[], options: any, element: any) {
this.overviewService.getOverviewAggBarData().pipe(first()).subscribe(comboRequest => {
for (const index of Object.keys(comboRequest.comboData)) {
comboRequest.comboData[index].unshift(comboBarLabels[index]);
}
const data_array = [comboBarTypes, comboRequest.comboData[0],
comboRequest.comboData[1], comboRequest.comboData[2]];
google.charts.load('current', {'packages': ['corechart']});
google.charts.setOnLoadCallback(() => {
const data = ChartService.createDataTable(data_array);
const chart = new google.visualization.ComboChart(element);
chart.draw(data, options);
});
});
}

我想要实现的是删除this.overviewService.getOverviewAggBarData()并用条件函数替换它，在 python 中是这样的：

def foo(a, b):  # Adds two numbers
return a + b
a = foo
print(a(1, 2))  # Prints 3

要制作如下所示的内容：

createCombo(comboBarLabels: String[], comboBarTypes: String[], options: any, element: any, source: any) {
if (source == "OverviewAggBar"){
get_data = this.overviewService.getOverviewAggBarData;
} else {
get_data = this.overviewService.getOverviewPieData;
}
get_data().pipe(first()).subscribe(comboRequest => {
for (const index of Object.keys(comboRequest.comboData)) {
comboRequest.comboData[index].unshift(comboBarLabels[index]);
}
const data_array = [comboBarTypes, comboRequest.comboData[0],
comboRequest.comboData[1], comboRequest.comboData[2]];
google.charts.load('current', {'packages': ['corechart']});
google.charts.setOnLoadCallback(() => {
const data = ChartService.createDataTable(data_array);
const chart = new google.visualization.ComboChart(element);
chart.draw(data, options);
});
});
}

我想这样做的原因是因为函数调用非常复杂，能够抽象出这部分为制作更通用的函数铺平了道路。实现相同目标的其他解决方案非常受欢迎！

解决了，这是新代码：

createCombo(comboBarLabels: String[], comboBarTypes: String[], options: any, element: any, source: string) {
let getData: any;
if (source === 'getAggData') {
getData = this.overviewService.getOverviewAggBarData.bind(this);
} else {
getData = this.overviewService.getOverviewPieData.bind(this);
}
getData().pipe(first()).subscribe(comboRequest => {
const data_array = [comboBarTypes];
for (const index of Object.keys(comboRequest.comboData)) {
comboRequest.comboData[index].unshift(comboBarLabels[index]);
data_array.push(comboRequest.comboData[index]);
}
google.charts.load('current', {'packages': ['corechart']});
google.charts.setOnLoadCallback(() => {
const data = ChartService.createDataTable(data_array);
const chart = new google.visualization.ComboChart(element);
chart.draw(data, options);
});
});
}

Answer 1

如果你有很多函数，你可以从源字符串创建一个"映射"到函数。然后，您可以向地图添加更多功能。像这样：

class YourClass {
private mapFromSourceToFunction: { [key: string]: () => Observable<YourComboResponseType> } = {
'getAggData': () => this.overviewService.getOverviewAggBarData(),
'getPipeData': () => this.overviewService.getOverviewPieData(),
'getSomethingElse': () => this.overviewService.getSomethingElse()
};
createCombo(comboBarLabels: String[], comboBarTypes: String[], options: any, element: any, source: string) {
let getData = this.mapFromSourceToFunction[source];
// getData().pipe ...
}
}

Answer 2

如果我理解正确，我认为你已经在那里了。JavaScript(和TypeScript(允许相同的行为。代码中缺少的是声明get_data。我会使用三元运算符来做到这一点：

const get_data = source === “OverviewAggBar” ? this.overviewService.getOverviewAggBarData : this.overviewService.getOverviewPieData;