javascript - 确保使用范围内的参数调用库中的函数

Question

我编写了一个接受对象作为参数的函数。所述对象包含各种附加参数。这与许多 jQuery 函数一样。

确保对象包含必需的最少参数的最佳方法是什么？如何为那些不需要的参数分配默认值？

这是我现在正在做的。

/*
	var options = {
		ListTitle: "",
		WebPartID: "",
		DisplayField: "Title",
		EnforceUnique: true,
		AllowEmpty: true,
		RequireSelection: true,
		NoSelectionMessage: "Please Select a Value",
		ConnectedWebPartID: ""
	}
	*/

	//Set Defaults.
	dropdownFilterOptions.DisplayField = (typeof dropdownFilterOptions.DisplayField === "undefined" ? "Title" : dropdownFilterOptions.DisplayField);
	dropdownFilterOptions.EnforceUnique = (typeof dropdownFilterOptions.EnforceUnique === "undefined" ? true : dropdownFilterOptions.EnforceUnique);
	dropdownFilterOptions.AllowEmpty = (typeof dropdownFilterOptions.AllowEmpty === "undefined" ? true : dropdownFilterOptions.AllowEmpty);
	dropdownFilterOptions.RequireSelection = (typeof dropdownFilterOptions.RequireSelection === "undefined" ? true : dropdownFilterOptions.RequireSelection);
	dropdownFilterOptions.NoSelectionMessage = (typeof dropdownFilterOptions.NoSelectionMessage === "undefined" ? "Please select a value." : dropdownFilterOptions.NoSelectionMessage);

	//Parameter Validation.
	var parameterValidationSuccess = true;
	if (typeof dropdownFilterOptions.ConnectedWebPartID === "undefined") {
		throw "ConnectedWebPartID is required!";
		parameterValidationSuccess = false;
	}
	if (typeof dropdownFilterOptions.ListTitle === "undefined") {
		throw "ListTitle is required.";
		parameterValidationSuccess = false;
	}
	if (typeof dropdownFilterOptions.WebPartID === "undefined") {
		throw "WebPartID is required.";
		parameterValidationSuccess = false;
	}
	if (!parameterValidationSuccess) return;

Answer 1

我想没有捷径可以检查所需的对象属性(必须一项一项地完成)。如果有人知道更好，请纠正我!

为了给不需要的参数赋值，Object.assign() 是一个不错的选择:

// parameterObject is passed into the function
// parameterObject === { prop1: "Peter", prop3: "yep", prop4: 500 }
var defaultObject = { prop1: "default value 1", prop2: "default value 2" };
var finalObject = Object.assign(defaultObject, parameterObject);
// finalObject === { prop1: "Peter", prop2: "default value 2", prop3: "yep", prop4: 500 }

在传递给函数的parameterObject 之上，被分配给defaultObject。这会覆盖所有可能从 parameterObject 中找到的 defaultObject 的属性，但不会影响仅属于 defaultObject 一部分的属性。

MDN:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign