In an array of objects I need to find a value
-- where key
is activity
: However the activity
key
can be deeply nested in the array like so:
const activityItems = [
{
name: 'Sunday',
items: [
{
name: 'Gym',
activity: 'weights',
},
],
},
{
name: 'Monday',
items: [
{
name: 'Track',
activity: 'race',
},
{
name: 'Work',
activity: 'meeting',
},
{
name: 'Swim',
items: [
{
name: 'Beach',
activity: 'scuba diving',
},
{
name: 'Pool',
activity: 'back stroke',
},
],
},
],
},
{} ...
{} ...
];
So I wrote a recursive algorithm to find out if a certain activity is in the array:
let match = false;
const findMatchRecursion = (activity, activityItems) => {
for (let i = 0; i < activityItems.length; i += 1) {
if (activityItems[i].activity === activity) {
match = true;
break;
}
if (activityItems[i].items) {
findMatchRecursion(activity, activityItems[i].items);
}
}
return match;
};
Is there an ES6
way of determining if an activity exists in an array like this?
I tried something like this:
const findMatch(activity, activityItems) {
let obj = activityItems.find(o => o.items.activity === activity);
return obj;
}
But this won't work with deeply nested activities.
Thanks
You can use some()
method and recursion to find if activity exists on any level and return true/false as result.
const activityItems = [{"name":"Sunday","items":[{"name":"Gym","activity":"weights"}]},{"name":"Monday","items":[{"name":"Track","activity":"race"},{"name":"Work","activity":"meeting"},{"name":"Swim","items":[{"name":"Beach","activity":"scuba diving"},{"name":"Pool","activity":"back stroke"}]}]}]
let findDeep = function(data, activity) {
return data.some(function(e) {
if(e.activity == activity) return true;
else if(e.items) return findDeep(e.items, activity)
})
}
console.log(findDeep(activityItems, 'scuba diving'))
We now use object-scan for simple data processing tasks like this. It's really good once you wrap your head around how to use it. Here is how one could answer your questions
// const objectScan = require('object-scan');
const find = (activity, input) => objectScan(['**'], {
abort: true,
rtn: 'value',
filterFn: ({ value }) => value.activity === activity
})(input);
const activityItems = [{"name":"Sunday","items":[{"name":"Gym","activity":"weights"}]},{"name":"Monday","items":[{"name":"Track","activity":"race"},{"name":"Work","activity":"meeting"},{"name":"Swim","items":[{"name":"Beach","activity":"scuba diving"},{"name":"Pool","activity":"back stroke"}]}]}]
console.log(find('scuba diving', activityItems));
// => { name: 'Beach', activity: 'scuba diving' }
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Disclaimer: I'm the author of object-scan
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