Rule proposal: no-useless-array-method
Description
In various situations, array methods are best avoided, because they create an intermediate array for no benefit. Typically this is the use of array.map() or array.filter() followed by direct iteration or another array method.
Fail
array.map(fn1).map(fn2)array.filter(fn1).filter(fn2)array.map(fn1).forEach(fn2)array.filter(fn1).forEach(fn2)array.map(fn1).reduce(fn2)array.filter(fn1).reduce(fn2)array.filter(fn1).find(fn2)for (const item of array.map(fn1)) {
fn2(item)
}for (const item of array.filter(fn1)) {
fn2(item)
}Pass
array.map(item => fn2(fn1(item)))array.filter(item => fn1(item) && fn2(item))array.forEach(item => {
fn2(fn1(item))
})array.forEach((item) => {
if (fn1(item)) {
fn2(item)
}
})array.reduce((acc, item) => {
return fn2(acc, fn1(item))
})array.reduce((acc, item) => {
if (fn1(item)) {
return fn2(acc, item)
}
return acc
})array.find((item) => fn1(item) && fn2(item))for (const value of array) {
const item = fn1(value)
fn2(item)
}for (const item of array) {
if (!fn1(item)) {
continue
}
fn2(item)
}Additional Info
This could be autofixable.
sindresorhus / eslint-plugin-unicorn
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