I have this small function (within my Angular 7 application) which uses JavaScript reduce(), and locates an object within a nested array of objects. I can then proceed to update certain properties on the fly.
Now, in addition to this find logic, I would like to also insert/delete an object into/from the nested array.
Question is: once I do locate my object, can I push() and/or delete an object ?
const input={UID:2,GUID:"",LocationName:"USA",ParentLocation:null,subs:[{UID:42,GUID:"",LocationName:"New Jersey",Description:"",subs:[{UID:3,GUID:"",LocationName:"Essex County",ParentLocation:null,"subs":[{UID:4,LocationName:"Newark",ParentLocation:3,"subs":[{"UID":49,"GUID":"","LocationName":"Doctor Smith's Office","LocationType":{"UID":2,"LocationTypeName":"Practice","Description":"other location"},"subs":[{"HostID":38,"HostName":"Ocean Host",}]}]}]}]}]};
const findUIDObj = (uid, parent) => {
const { UID, subs } = parent;
if (UID === uid) {
const { subs, ...rest } = parent;
return rest;
}
if (subs) return subs.reduce((found, child) => found || findUIDObj(uid, child), null);
};
console.log(findUIDObj(49, input));
var obj = findUIDObj(49, input);
delete obj; For example, in my Angular 7 app, it complains if I attempt to delete the found object:
ex/
var obj = findUIDObj(49, input);
delete obj;
'delete' cannot be called on an identifier in strict mode.
delete obj would never do what you want: first of all, it is not even an object from your input, since the function created a new object from the found object, excluding the subs property, and returned that. But more importantly, delete is used for deleting properties, not objects.
It seems you want to remove a matching object from its parent subs property. For that you would need to mutate the subs array, so it would exclude the matching object. For that to work in a generic way, your input should be an array. Otherwise that root object could not be removed from anything.
With that in mind, your lookup function should return the array in which the match was found and at which index. With those pieces of information you can decide to remove that element from the array, or to insert another object at that index.
Here is how it could work with removal:
const input=[{UID:2,GUID:"",LocationName:"USA",ParentLocation:null,subs:[{UID:42,GUID:"",LocationName:"New Jersey",Description:"",subs:[{UID:3,GUID:"",LocationName:"Essex County",ParentLocation:null,"subs":[{UID:4,LocationName:"Newark",ParentLocation:3,"subs":[{"UID":49,"GUID":"","LocationName":"Doctor Smith's Office","LocationType":{"UID":2,"LocationTypeName":"Practice","Description":"other location"},"subs":[{"HostID":38,"HostName":"Ocean Host",}]}]}]}]}]}];
const findUIDObj = (uid, arr) => {
if (!arr) return;
const idx = arr.findIndex(obj => obj.UID === uid);
if (idx > -1) return [arr, idx];
for (const obj of arr) {
const result = findUIDObj(uid, obj.subs);
if (result) return result;
}
};
console.log(findUIDObj(49, input));
const [arr, idx] = findUIDObj(49, input) || [];
if (arr) {
arr.splice(idx, 1); // Remove object from its parent array
}Collected from the Internet
Please contact [email protected] to delete if infringement.
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