I have an Object with this structure that I instantiate all around the code
costs: {
totalPerYear,
totalEver,
perMonth: {
items: {
depreciation,
insurance,
credit,
inspection,
roadTaxes,
fuel,
maintenance,
repairsImprovements,
parking,
tolls,
fines,
washing
},
standingCosts,
runningCosts,
total
},
perUnitDistance: {
runningCosts,
totalCosts
}
}
I've been reading about constructors and instantiation . Is there a way, for the sake of conciseness , to have a constructor for this object wherein all the variables are set to undefined
, like what happens when we define a variable var x;
?
I have the obvious solution
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();
Which techniques do you use to create an object with a complex structure?
If you just want an object and don't need it to have a special prototype, a function returning an object rather than a constructor is quite straightforward:
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
}
}
};
}
Example:
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; }
There is, of course, nothing to prevent your giving yourself a shorter name to use within costs
:
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
}
}
};
}
Example:
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; }
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.