The findIndex() method will consistently return a value of -1 when used on an array

Question

The findIndex() method will consistently return a value of -1 when used on an array

I am struggling to find a solution for the following problem. Instead of returning 1, the index is always -1 in this case.

Can anyone assist me with this?

let allRules = [{ruleName: "a"}, {ruleName: "b"}, {ruleName: "c"}]
let name = "b"
let index = allRules.findIndex(x => {
  console.log(x.ruleName)
  x.ruleName === name
})
console.log(index)

javascript arrays typescript

Answer 1

Answer №1

To ensure proper functionality, remember to utilize the return keyword when working with callback methods that include empty curly braces:

let allItems = [{itemName: "apple"}, {itemName: "banana"}, {itemName: "cherry"}]
let itemToFind = "banana"
let itemIndex = allItems.findIndex(x => {
  console.log(x.itemName)
  return x.itemName == itemToFind
})
console.log(itemIndex)

Here is an example of a similar function without the return statement:

let allItems = [{itemName: "apple"}, {itemName: "banana"}, {itemName: "cherry"}]
let itemToFind = "banana"
let itemIndex = allItems.findIndex(x => x.itemName == itemToFind)
console.log(itemIndex)

Answer 2

To ensure proper functionality, remember to utilize the return keyword when working with callback methods that include empty curly braces:

let allItems = [{itemName: "apple"}, {itemName: "banana"}, {itemName: "cherry"}]
let itemToFind = "banana"
let itemIndex = allItems.findIndex(x => {
  console.log(x.itemName)
  return x.itemName == itemToFind
})
console.log(itemIndex)

Here is an example of a similar function without the return statement:

let allItems = [{itemName: "apple"}, {itemName: "banana"}, {itemName: "cherry"}]
let itemToFind = "banana"
let itemIndex = allItems.findIndex(x => x.itemName == itemToFind)
console.log(itemIndex)

Answer 3

Answer №2

To solve the problem, make sure to include a return statement in your code.

let allRules = [{ruleName: "a"}, {ruleName: "b"}, {ruleName: "c"}]
let name = "b"
let index = allRules.findIndex(x => {
  console.log(x.ruleName)
  return x.ruleName === name
})
console.log(index)

Answer 4

To solve the problem, make sure to include a return statement in your code.

let allRules = [{ruleName: "a"}, {ruleName: "b"}, {ruleName: "c"}]
let name = "b"
let index = allRules.findIndex(x => {
  console.log(x.ruleName)
  return x.ruleName === name
})
console.log(index)

Answer 5

Answer №3

According to @Nick Parsons' comment, it is necessary to include a return statement in your code.

let allRules = [{ruleName: "a"}, {ruleName: "b"}, {ruleName: "c"}]
let name = "b"
let index = allRules.findIndex(x => {
  console.log(x.ruleName);
  return x.ruleName === name;
})
console.log(index)

Answer 6

According to @Nick Parsons' comment, it is necessary to include a return statement in your code.

let allRules = [{ruleName: "a"}, {ruleName: "b"}, {ruleName: "c"}]
let name = "b"
let index = allRules.findIndex(x => {
  console.log(x.ruleName);
  return x.ruleName === name;
})
console.log(index)

The findIndex() method will consistently return a value of -1 when used on an array

Answer №1

Answer №2

Answer №3

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