Assume we have the following arrays of objects to be compared based on property id:
a = [{'id':'1', 'name':'a1'}, {'id':'2', 'name':'a2'}, {'id':'3', 'name':'a3'}]
and
b = [[{'id':'2', 'name':'a2'}, ]
How can I subtract b from a? So that we have c = a - b which should be equal to [ {'id':'1', 'name':'a1'}, {'id':'3', 'name':'a3'}].
I have tried using this:
var c= a.filter(function(item) {
return !b.includes(item.id);
});
but still not working.
Advertisement
Answer
How about this solution? It assumes that ‘b’ is also an array so for each element of ‘a’ you check if there is a matching object in ‘b’. If there is a matching object then return a false in the filter function so that that element is discarded.
var a = [{
'id': '1',
'name': 'a1'
}, {
'id': '2',
'name': 'a2'
}, {
'id': '3',
'name': 'a3'
}]
var b = [{
'id': '2',
'name': 'a2'
}]
var c = a.filter(function(objFromA) {
return !b.find(function(objFromB) {
return objFromA.id === objFromB.id
})
})
console.log(c)