数组对象的javascript迭代逻辑XOR？

Question

I have a function that loops over 2 arrays of Feature objects and checks if each Feature's active property has changed. So far I have this:

const changes = [];

let index = 0;

features.forEach((feature) => {

  if (feature.active && !originalFeatures[index].active) {
    return changes.push({ name: feature.name, change: 'Activated' });
  }

  if (!feature.active && originalFeatures[index].active) {
    return changes.push({ name: feature.name, change: 'Deactivated' });
  }

  index += 1;
});

A) The code doesn't work, there's a logic error I can't seem to bust. After changing the active state of a single feature, the function outputs changes as an array of half the features being 'Activated'. Note I have asserted the two input arrays as containing the correct objects and property values before the function is run.

B) is there a faster built in function that could simplify the process from these if statements?

Am relatively new to javascript so any ideas would be greatly appreciated, thanks

Answer 1

is there a faster way that could simplify the process from these if statements?

Sure, just write a single statement

if (feature.active != originalFeatures[index].active) {
    return changes.push({
        name: feature.name,
        change: feature.active ? 'Activated' : 'Deactivated'
    });
}

You could also use the actual XOR operator ^ but since we are working with booleans here I prefer != .

Answer 2

I prefer the use of Array.prototype.map , Array.prototype.filter and Array.prototype.reduce over Array.prototype.forEach .

Untested:

const changes = features.reduce((filtered, feature, index) => {
    if (feature.active ^ originalFeatures[index].active) {
        filtered.push({ name: feature.name, change: (feature.active) ? 'Activated' : 'Deactivated' }})
    }
    return filtered;
 }, []);