Is there a simpler way to write this on one line in TypeScript?-CodePudding

I have the following snippet that I m feeling it ugly and code repeatitive, is there any better way to achieve it more elegantly and performance freindly ?

            let id : number;
            if((<ParameterModel>this.activeNodeRule.node.data).parameterId){
                id = (<ParameterModel>this.activeNodeRule.node.data).parameterId
            }else{
                id = (<RuleModel>this.activeNodeRule.node.data).parameter.parameterId
            }

CodePudding user response：

Assuming you already have a proper typing, ie this.activeNodeRule.node.data is already known to be of type ParameterModel | RuleModel at compiletime, I'd suggest to implement a type predicate. Then you can do something like the following

let data : ParameterModel | RuleModel = this.activeNodeRule.node.data;
let id = isParameterModel(data) ? data.parameterId : data.parameter.parameterId;

If you don't have proper typing, ie the type of data is entirely unknown at compiletime, you could do as follows:

let data = this.activeNodeRule.node.data as unknown;
let id: number;
if (isParameterModel(data)) id = data.parameterId;
else if (isRuleModel(data)) id = data.parameter.parameterId;
else //do whatever needs to be done, if data is any other type.

This IMHO is the cleanest way to deal with such a situation. Good code is not always about being as short as possible, but also should be readable and understandable ...

CodePudding user response：

If you need validate first if parameterId exists and if not asign parameter.parameterId

id = (<ParameterModel>this.activeNodeRule.node.data).parameterId?(<ParameterModel>this.activeNodeRule.node.data).parameterId:(<RuleModel>this.activeNodeRule.node.data).parameter.parameterId

if you can validate first parameter

id = (<ParameterModel>this.activeNodeRule.node.data).parameter?.parameterId

CodePudding user response：

You could do something like:

const data = this.activeNodeRule.node.data
const id = data?.parameterId ?? data?.parameter?.parameterId

This might not be type-safe depending on your context though, you may have to add a bang ! somewhere.

CodePudding user response：

What is the type of data. Is it ParameterModel | RuleModel? Does parameterId not exist on RuleModel? Assuming those two, you can do something like:

const data = this.activeNodeRule.node.data;
const id = 'parameterId' in data ? data.parameterId : data.parameter.parameterId;

Depending on your TS config, the other answers might only work if parameterId also exists on RuleModel.

Edit: Actually, if you can, do the type predicate. It's better.