Shorten if else statement-CodePudding

How can I shorten that if else statement?

const isPathPointAvailable = (requiredItems?: ModelTypes['Item'][], oneOfItems?: ModelTypes['Item'][]) => {
    if(requiredItems && requiredItems.length > 0){
        return userHaveMultipleRequiredItems(requiredItems);
    }
    if(oneOfItems && oneOfItems.length > 0){
        return userHaveRequiredItem(oneOfItems);
    }
    return true

I tried this but it always return true

const isPathPointAvailable = (requiredItems?: ModelTypes['Item'][], oneOfItems?: ModelTypes['Item'][]) => {
    requiredItems && requiredItems.length > 0 && userHaveMultipleRequiredItems(requiredItems);
    oneOfItems && oneOfItems.length > 0 && userHaveRequiredItem(oneOfItems);
    return true
};

CodePudding user response：

Use the optional chaining operator ?. to return the falsy undefined if the arrays are not defined. length === 0 is also falsy.

const isPathPointAvailable = (requiredItems?: ModelTypes['Item'][], oneOfItems?: ModelTypes['Item'][]) => {
    if(requiredItems?.length) return userHaveMultipleRequiredItems(requiredItems);
    if(oneOfItems?.length) return userHaveRequiredItem(oneOfItems);
    return true

You were on the right track with your second attempt, but it is missing the return statements in the shortened ifs.

CodePudding user response：

You could also just use a simple lambda to refactor those two longer checks with something like:

let isNotEmpty = (arr) => arr && arr.length > 0;

const isPathPointAvailable = (requiredItems?: ModelTypes['Item'][], oneOfItems?: ModelTypes['Item'][]) => {
  if( isNotEmpty(requiredItems) ) {
    return userHaveMultipleRequiredItems(requiredItems);
  }
  if( isNotEmpty(oneOfItems) ) {
    return userHaveRequiredItem(oneOfItems);
  }
  return true
}

That would keep the same semantics, but having a function called isNotEmpty(...) vs. !isEmpty(...) is maybe not as "stylish." So if you prefer the later it would mean you'd need to invert the boolean logic:

 let isEmpty = (arr) => !arr || arr.length === 0;