構造具有復雜結構的Javascript對象？

Question

我有一個具有這種結構的對象，可以在代碼周圍實例化所有對象

costs: {
    totalPerYear,
    totalEver,

    perMonth: {
        items: {
            depreciation,
            insurance,
            credit,
            inspection,
            roadTaxes,
            fuel,
            maintenance,
            repairsImprovements,
            parking,
            tolls,
            fines,
            washing
        },
        standingCosts,
        runningCosts,
        total
    },

    perUnitDistance: { 
        runningCosts,
        totalCosts
    }
}

我一直在閱讀有關構造函數和實例化的內容 。 為了簡潔起見 ，有沒有辦法為此對象提供一個構造函數，其中所有變量都設置為undefined ，就像定義變量var x;時發生的情況一樣var x; ？

我有明顯的解決方案

function Costs(){
    this.totalPerYear = undefined;
    this.totalEver = undefined;

    this.perMonth = {
        items: {
            depreciation: undefined,
            insurance: undefined,
            credit: undefined,
            inspection: undefined,
            roadTaxes: undefined,
            fuel: undefined,
            maintenance: undefined,
            repairsImprovements: undefined,
            parking: undefined,
            tolls: undefined,
            fines: undefined,
            washing: undefined                        
        },
        standingCosts: undefined,
        runningCosts: undefined,
        total: undefined
    };

    this.perUnitDistance = { 
        runningCosts: undefined,
        totalCosts: undefined
    };
};

var userCosts = new Costs();

您使用哪些技術來創建具有復雜結構的對象？

Answer 1

如果只需要一個對象，而不需要它具有特殊的原型，則返回對象而不是構造函數的函數非常簡單：

function costs() {
    return {
        costs: {
            totalPerYear: undefined,
            totalEver: undefined,

            perMonth: {
                items: {
                    depreciation: undefined,
                    insurance: undefined,
                    credit: undefined,
                    inspection: undefined,
                    roadTaxes: undefined,
                    fuel: undefined,
                    maintenance: undefined,
                    repairsImprovements: undefined,
                    parking: undefined,
                    tolls: undefined,
                    fines: undefined,
                    washing: undefined
                },
                standingCosts: undefined,
                runningCosts: undefined,
                total: undefined
            },

            perUnitDistance: { 
                runningCosts: undefined,
                totalCosts: undefined
            }
        }
    };
}

例：

 function costs() { return { costs: { totalPerYear: undefined, totalEver: undefined, perMonth: { items: { depreciation: undefined, insurance: undefined, credit: undefined, inspection: undefined, roadTaxes: undefined, fuel: undefined, maintenance: undefined, repairsImprovements: undefined, parking: undefined, tolls: undefined, fines: undefined, washing: undefined }, standingCosts: undefined, runningCosts: undefined, total: undefined }, perUnitDistance: { runningCosts: undefined, totalCosts: undefined } } }; } console.log(costs()); 

 .as-console-wrapper { max-height: 100% !important; } 

當然，沒有什么可以阻止您在costs范圍內給自己起一個簡短的名字：

function costs() {
    const u = undefined;
    return {
        costs: {
            totalPerYear: u,
            totalEver: u,

            perMonth: {
                items: {
                    depreciation: u,
                    insurance: u,
                    credit: u,
                    inspection: u,
                    roadTaxes: u,
                    fuel: u,
                    maintenance: u,
                    repairsImprovements: u,
                    parking: u,
                    tolls: u,
                    fines: u,
                    washing: u
                },
                standingCosts: u,
                runningCosts: u,
                total: u
            },

            perUnitDistance: { 
                runningCosts: u,
                totalCosts: u
            }
        }
    };
}

例：

 function costs() { const u = undefined; return { costs: { totalPerYear: u, totalEver: u, perMonth: { items: { depreciation: u, insurance: u, credit: u, inspection: u, roadTaxes: u, fuel: u, maintenance: u, repairsImprovements: u, parking: u, tolls: u, fines: u, washing: u }, standingCosts: u, runningCosts: u, total: u }, perUnitDistance: { runningCosts: u, totalCosts: u } } }; } console.log(costs()); 

 .as-console-wrapper { max-height: 100% !important; }