I am trying to get a new array object based on two of them.
log1 = {1:"London",2:"New york",4:"Berlin"};
log2 = [{id:1, location:"EU"},{id:2, location:"US"},{id:18, location:"Asia"}];
I want to make sure that log1 keys all exist in log2 and, if not, I want to delete it. So for this will be:
result = {1:"London",2:"New york"};
I couldn't do it with filter as it take only one object. Is there any way to filter based on two object arrays? Is there any neat way to do it ?
If you are using a recent version of JS with Array.map(), Array.filter() and Object.keys() you could try the following for a slightly more functional approach:
var log1 = {
1: "London",
2: "New york",
4: "Berlin"
};
var log2 = [
{id: 1, location: "EU"},
{id: 2, location: "US"},
{id: 18, location: "Asia"}
];
var ids = log2.map(function(obj) { return obj.id; }).map(String);
Object.keys(log1).filter(function(key) {
return ids.indexOf(key) === -1;
}).forEach(function(k) {
delete log1[k];
});
console.log(log1);
Should yield:
{ '1': 'London', '2': 'New york' }
Example: http://repl.it/RnF/2
Hope this helps :)
Edit
Otherwise, for browser compatibility and much more you could consider lodash or underscore as suggested by other posters. Or use a polyfill!
MDN provides polyfills at the bottom of each of the following pages for older environments (in case you require the compatibility):
return '' + obj.id; is just a shortcut to cast the id values from log2 from number to string because Object.keys() will return numeric keys from log1 as strings.
log2.map(function(obj){ return obj.id }).map(String)
Here is how you can do it in pure js:
log1 = {1:"London",2:"New york",4:"Berlin"};
log2 = [{id:1, location:"EU"},{id:2, location:"US"},{id:18, location:"Asia"}];
for (var prop1 in log1) {
var found = false;
for (var i = 0; i < log2.length; i++) {
if (log2[i].id.toString() === prop1) {
found = true;
break;
}
}
if (!found) {
delete log1[prop1]
}
}
It has pluck,filter and map functions that can help you out.. Its quite powerful..
