CODEWITHSUNDEEP
javascript
user3438958
user3438958

Reputation:

Javascript: true and false comparisons with 0 and 1 numbers

When working with ajax requests, if a response property is either 1 (type: number) for true or 0 (type: number) for false, what is the best way to check if this is true. All of these examples work, just wondering if there is a preferred one to use and the reason it is preferred.

if (response.hasOwnProperty('test')) {

    // 1
    if (response.test === 1) {
        alert('is true');
    }

    // 2
    if (response.test) {
        alert('is true');
    }

    // 3
    if (response.test == true) {
        alert('is true');
    }

    // 4
    if (Boolean(response.test) === true) {
        alert('is true');
    }

    // 5
    if (response.test == 1) {
        alert('is true');
    }
}

Upvotes: 1

Views: 70

Answers (1)

ZER0
ZER0

Reputation: 25322

As was said, it's mostly opinion based.

However, there are some pro and cons depends by the approach you're using.

First of all, the context is important: if it's code you're writing for yourself or it's a project with other developers that are collaborating; if you also wrote - and therefore you have control - on the backend, and so on.

In general, if it's something I've control AND it's not a production code, I would probably go for the second form: quick enough, clear enough - it's truthy or falsy - and I'm sure that the value returned from the backend are 0 and 1 for a reason.

In all the other scenario, I would go for the strict equal, so the first form: it's more explicit. Reading the second form, the only thing I know is that the value can be truthy or falsy, I've no idea what the actual value can be. If there is any change in the API - because, for instance, I do not have direct control on it, or maybe someone else change it in the project and forgot this piece of code - the code would fail. For example:

if (response.test === 1) {
  // do something
} else if (response.test === 0) {
  // do something else or do nothing
} else {
  throw new Error("Unexpected value from response.test")
}

Even if you don't have the else would be safe enough if the API would add a new value. For example, let's say that now the API can returns 0, 1, or 3. If you check for truthy values, 1 and 3 will be equals. But if you have:

if (response.test === 1) {
  // do something
} else if (response.test === 0) {
  // do something else or do nothing
}

You're good; your code will still works as intended, even if the API is extended.

Upvotes: 1

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