static"的正确结构Javascript中的类型对象

Correct structure for "static" type objects in Javascript

本文关键字：Javascript 类型 对象 结构 quot static      更新时间：2023-09-26

我正在努力掌握在JavaScript中创建"静态"对象类型(我怀疑我的措辞是否正确…)。

在下面的代码中，我试图创建一个jQuery插件(我怀疑这是无关紧要的，虽然)，它创建多个CrmQuery，每个都有自己的上下文信息作为instance传入。我还想为所有CrmQuery创建一个"静态"对象来使用(它可以是无状态的)，并希望将其包含在CrmQuery名称空间中。

这是我的结构，但是当调用CrmQuery.searchOperator[instance.Operator].buildCondition(instance.fieldName, searchTerm)时，buildCondition函数不能访问CrmQuery.searchOperator中的oDataOperator函数。我试过以多种方式引用它，而不仅仅是searchOperator.oDataOperator, this是对实际属性的引用，而不是CrmQuery.searchOperator。

结构:

(function($) { 
...
var crmQuery = new CrmQuery(instance);
var data = crmQuery.searchCrm(searchTerm);
... 
var CrmQuery = function(instance) {
    ...
    this.oDataUrl = function() {
        ...
        oDataFilter += CrmQuery.searchOperator[instance.Operator].buildCondition(instance.fieldName, searchTerm);
        ...
        return oDataFilter;
    }();
    this.searchCrm(searchTerm) {
        ...
        url += this.oDataUrl;
    }
    ...
}
CrmQuery.searchOperator = {
    oDataFunctionOperator: function oDataFunctionOperator(fieldName, searchTerm, operator) {
        return operator + "(" + fieldName + ", '" + searchTerm + "')";
    },
    oDataOperator: function oDataOperator(fieldName, searchTerm, operator) {
        return fieldName + " " + operator + " '" + searchTerm +"'";
    },
    STARTSWITH: { 
        operator: "startswith", 
        buildCondition: function(fieldName, searchTerm) { 
                return this.oDataFunctionOperator(fieldName, searchTerm, this.operator) 
            }
    },
    ENDSWITH: { 
        operator: "endswith", 
        buildCondition: function(fieldName, searchTerm) { 
                return searchOperator.oDataFunctionOperator(fieldName, searchTerm, this.operator) 
            }
    },
    CONTAINS: { 
        operator: "substringof", 
        buildCondition: function(fieldName, searchTerm) { 
                return searchOperator.oDataFunctionOperator(fieldName, searchTerm, this.operator) 
            }
    },
    EXACTMATCH: { 
        operator: "eq", 
        buildCondition: function(fieldName, searchTerm) { 
                return searchOperator.oDataOperator(fieldName, searchTerm, this.operator) 
            }
    },
    toString: function () {
        var thisVar = this;
        var output = "searchOperator enum. ";
        output += $.map(Object.keys(this), function (i) {
            if (typeof thisVar[i] !== "function") 
                return i + ": " + thisVar[i].operator;
        }).join(", ");
        return output;
    }
}
...
}(jQuery));

在JavaScript中实现这样的模式的正确方法是什么?

我希望这是有意义的?如果太啰嗦，我很抱歉，但我不想遗漏任何可能重要的东西。

很多谢谢,詹姆斯。

继承是解决这个问题的一种方法，例如:

function searchOperator() {
}
//searchOperator.prototype.toString = ...
functionOperator = function(operator) {
    searchOperator.apply(this);
    this.operator = operator;
}
functionOperator.prototype = Object.create(searchOperator.prototype);
functionOperator.prototype.buildCondition = function (fieldName, searchTerm) {
    return this.operator + "(" + fieldName + ", '" + searchTerm + "')";
}
operators = {
    STARTSWITH: new functionOperator('startswith')
}
console.log(operators.STARTSWITH.buildCondition('foo', 'bar'))
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