Complex .reduce to filter an array - reduce

Question

so I'm trying to write a fancy reduce function (i could loop, but ...). Would love help on this -
The initial items array:
const items = [
{'labels': ['a'], 'team': "infra"},
{'labels': [], 'team': "infra"},
{'labels': [], 'team': "InfraNew"},
{'labels': ['new'], 'team': "infrastructure org"},
{'labels': ['aaa'],'team': "infra"},
{'labels': [], 'team': "Infra 1"},
{'labels': ['b'],'team': "infra"},
{'labels': ['a'],'team': "DT"},
{'labels': ['c'], 'team': "DT"},
{'labels': ['c', 'b'], 'team': null}
]
and the filters object.
const filters = {
team: ['infra', 'DT'],
labels: ['a', 'b']
}
The goal is to get results array of items, with labels within the filtered teams. (So if teams don't have matching labels, they should be excluded).
const results = [
{'labels': ['a'],'team': "infra"},
{'labels': ['b'],'team': "infra"},
{'labels': ['a'],'team': "DT"},
]
This is what I have, but can't seem to get the conditioning correctly.
function filtering(res, el) {
for (let i = 0; i < Object.keys(filters).length; i++) {
const key = Object.keys(filters)[i];
let filterArray = filters[key];
const elementValue = el[key];
if (!elementValue) return res;
if (key === 'labels') {
if (elementValue.length === 0) return res;
elementValue.map(elementValueItem => {
if (filterArray.indexOf(elementValueItem) < 0) {
return res
}
})
} else if (filterArray.indexOf(elementValue) < 0) {
return res;
}
}
res.push(el);
return res;
}
var results = items.reduce(filtering, [])
console.log(results)
Here is the jsfiddle

Answer 1

It would greatly simplify your conditions if you thought about this problem in terms of Array.prototype.filter. I've done that for you below
const items = [
{'labels': ['a'], 'team': "infra"},
{'labels': [], 'team': "infra"},
{'labels': [], 'team': "InfraNew"},
{'labels': ['new'], 'team': "infrastructure org"},
{'labels': ['aaa'],'team': "infra"},
{'labels': [], 'team': "Infra 1"},
{'labels': ['b'],'team': "infra"},
{'labels': ['a'],'team': "DT"},
{'labels': ['c'], 'team': "DT"},
{'labels': ['c', 'b'], 'team': null},
]
const filters = {
team: ['infra', 'DT'],
labels: ['a', 'b'],
}
const shouldKeep = item => {
if (!filters.team.includes(item.team)) {
return false
}
if (item.labels.length === 0) {
return false
}
for (const label of item.labels) {
if (!filters.labels.includes(label)) {
return false
}
}
return true
}
console.log(
items.filter(shouldKeep)
)