Right now, if 'Everything' in the list is detected, the output becomes [""].
Expected output: []
Copy.names = rule.names.map(function(x) {
if (x.name ==='Everything') {
return '';
} else {
return x.name;
}
});
Use Array.prototype.filter:
Copy.names = rule.names.filter(function(x) {
return x.name !=='Everything';
}).map(function (x) {
return x.name;
});
x.name !== 'Everything'?Another solution with Array.filter():
names.map(
(x) => x.name === 'Everything' && x.name
).filter(Boolean)
If you can use Lodash (which I highly recommend), you can deal with it in elegant way by using _.flatMap:
Copy.names = _.flatMap(rule.names, function(x) {
if (x.name ==='Everything') {
return [];
} else {
return [x.name];
}
})
As you can see, it's similiar to map, except that you return array of items instead of item.
If you can use ES6, you can use generator for that:
Copy.names = Array.from(function* () {
for (var x of rule.names) {
if (x.name ==='Everything') {
// do nothing
} else {
yield x.name;
}
}
})
If not... you can always go for imperative way:
Copy.names = []
for (var x of rule.names) {
if (x.name ==='Everything') {
// do nothing
} else {
Copy.names.push(x.name);
}
}
An answer I wrote elsewhere covers this, but if you want to be able to accomplish the transform of Array.map() but also to change the output length, you would need to use Array.reduce().
Usually, though, it will make more sense to filter--preferably before you map, but if needed, then after.
For this you should use reduce instead of map, here an example:
Copy.names = rule.names.reduce(function (arr, x) {
x.name !== 'Everything' && arr.push(x.name)
return arr
}, [])
return;Also, consider using Array.prototype.filter for this.filter.mapreturns an element for every element you iterate over.maptofilter,return ''tofalseandreturn x.nametotruereturn x.name === 'Everything'instead of the whole if...else