I've noticed that with all the new features being added to JavaScript, there still isn't a shorthand for adding values where null is treated as zero. It's a bit of a hassle to have to check for null or zero before doing the addition. For instance, I often find myself writing code like this:
```javascript
const obj = {};
for (const item of list) {
if (!obj[item.id]) obj[item.id] = 0;
obj[item.id] += item.amount;
}
```
Or using the nullish coalescing operator:
```javascript
const obj = {};
for (const item of list) {
obj[item.id] = (obj[item.id] ?? 0) + item.amount;
}
```
It would be much simpler if I could just write something like this:
```javascript
const obj = {};
for (const item of list) {
obj[item.id] +== item.amount;
}
```
2 Answers
It's usually better to treat null values as potential bugs rather than just defaults. PS: Using the nullish coalescing assignment operator can help: `obj[item.id] ??= 0; obj[item.id] += item.amount;`
You could go with the nullish coalescing operator (??) which does almost what you're asking for. This keeps your code clearer and avoids potential confusion down the line. Like this: `obj[item.id] = (obj[item.id] ?? 0) + item.amount;`
Good point!