"In a single line, add an item to an array based on a specified condition

Question

"In a single line, add an item to an array based on a specified condition

I am trying to achieve something similar in JavaScript with a one-liner. Can this be done without using an if statement?

// These versions add false to the array if condition = false
let arr = await getArray(params).push(condition && itemToAdd);
arr = await getArray(params).push((() => condition && itemToAdd)());

// This version adds undefined to the array if condition = false
arr = await getArray(params).push((() => { if (condition) return itemToAdd })());

(I included the getArray part because that's how it appears in my code and the array is not saved as a variable arr. It is immediately returned to its calling function, hence the aim to avoid adding an extra line for the if statement...)

javascript arrays

Answer 1

Answer №1

There may not be a clear reason for wanting to condense this into a single line, but here's one way it could be done:

let arr = [...await getArray(), itemToAdd].slice(0, condition ? undefined : -1);

In this code snippet, we are adding the itemToAdd to the array regardless of the condition. However, if the condition is false, we then remove the last element (itemToAdd) from the array.

Answer 2

There may not be a clear reason for wanting to condense this into a single line, but here's one way it could be done:

let arr = [...await getArray(), itemToAdd].slice(0, condition ? undefined : -1);

In this code snippet, we are adding the itemToAdd to the array regardless of the condition. However, if the condition is false, we then remove the last element (itemToAdd) from the array.

Answer 3

Answer №2

When working with reactjs, useState can be utilized for managing conditions.

const [isCondition, setIsCondition] = useState(false);

//However, if/else statements are needed to modify the state of useState

if(this_condition_occurs) {

setIsCondition(true) } else { setIsCondition(false) }

//An alternative approach is demonstrated below

let array = await retrieveArray(parameters).push(isCondition && itemToAdd);

Answer 4

When working with reactjs, useState can be utilized for managing conditions.

const [isCondition, setIsCondition] = useState(false);

//However, if/else statements are needed to modify the state of useState

if(this_condition_occurs) {

setIsCondition(true) } else { setIsCondition(false) }

//An alternative approach is demonstrated below

let array = await retrieveArray(parameters).push(isCondition && itemToAdd);

"In a single line, add an item to an array based on a specified condition

Answer №1

Answer №2

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