如何从另一个对象数组中按字面值减去一个对象数组

Question

I think my question is pretty easy but as I am beginning to learn javascript I'm stuck with the following. I have 2 object arrays which contain some same Ids which can be multiple duplicates. I want to subtract the same Ids in the arrays from each other with plain javascript no libraries. I found this filter method but it removes all the objects with the criteria. I expect only the amount of Ids removed fulfilling the criteria which can be found in the array to be subtracted.

Here is my example:

var filter = [{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Categorie__c"},{"Id":"124","Name":"OPL-00074051","arrayPicklist":"Categorie__c"}]   
var filter2 = [{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Categorie__c"},{"Id":"123","Name":"OPL-00074051","arrayPicklist":"Categorie__c"},{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Regio__c"}]     
var newFilter = filter2.filter(o => !filter.find(o2 => o.Id === o2.Id &&  o.arrayPicklist === o2.arrayPicklist));
console.log(JSON.stringify(newFilter));

http://jsfiddle.net/vy6fcgrc/29/

I expect:

newFilter = [{"Id":"123","Name":"OPL-00074051","arrayPicklist":"Categorie__c"},{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Regio__c"}]

Answer 1

 var filter1 = [{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Categorie__c"}, {"Id":"124","Name":"OPL-00074051","arrayPicklist":"Categorie__c"}] var filter2 = [{"Id":"123","Name":"OPL-00074045","arrayPicklist":"Categorie__c"}, {"Id":"123","Name":"OPL-00074051","arrayPicklist":"Categorie__c"}, {"Id":"123","Name":"OPL-00074045","arrayPicklist":"Regio__c"}] var props = ["Id","Name", "arrayPicklist"]; var result = filter1.filter(function(o1){ // filter out (!) items in result2 return !filter2.some(function(o2){ return (o1.Id === o2.Id && o1.arrayPicklist===o2.arrayPicklist) ; // assumes unique id }); }).map(function(o){ // use reduce to make objects with only the required properties // map to apply this to the filtered array as a whole return props.reduce(function(newo, arrayPicklist){ newo[arrayPicklist] = o[arrayPicklist]; return newo; }, {}); }); alert(JSON.stringify(result));