Remove unnecessary memoization from a code example

[kopeczech]

---

name: 📝 Documentation Fix
about: Removing unnecessary memoization from a code example as it might confuse people

What docs page needs to be fixed?

• Section: Writing Memoized Selectors with Reselect
• Page: Deriving Data with Selectors

What is the problem?

Using (createSelector) for the selectA1 selector directly contradicts the Balance Selector Usage section, which says in bold text the following: A selector function that does a direct lookup and return of a value should be a plain function, not memoized. Therefore this code example might confuse people about when to use memoization.

const state = {
  a: {
    first: 5
  },
  b: 10
}

const selectA = state => state.a
const selectB = state => state.b

const selectA1 = createSelector([selectA], a => a.first)

const selectResult = createSelector([selectA1, selectB], (a1, b) => {
  console.log('Output selector running')
  return a1 + b
})

const result = selectResult(state)
// Log: "Output selector running"
console.log(result)
// 15

const secondResult = selectResult(state)
// No log output
console.log(secondResult)
// 15

What changes does this PR make to fix the problem?

Not using createSelector for this one.

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[timdorr]

Thanks!

[markerikson]

Yeah, honestly we need a more realistic example here. Would appreciate a PR for that if you're interested!