CODEWITHSUNDEEP
javascriptobject
user1486133
user1486133

Reputation: 1487

Validating if object data is "true" and retrieving relevant data if so

I have a problem to solve using some data from an object. The data could take a few forms and may or may not exist in the first place. For example

things : {
   oranges: true,
   apples : false
}

but it could equally be: 

things : {
   oranges: false,
   apples : false
}

or maybe things doesn't even exist

I need to:

1) Determine that things exists

2) Determine that things contains further keys

These two statements need to be verified in one callable function e.g thingsHasData()

3) If things does have data, is any of the data set to true?

This also needs to be a callable function e.g fruitsIsTrue()

4) Return the key for one of the true values

trueFruit() - this should only return one key, but it doesn't matter which (it shouldn't ever have two true values as per business rules but it's more of a fallback to just return one if for some reason it does)

So I've been able to get the key of a true key-value pair using the following:

var thingsList = {
    things : {
           oranges: false,
           apples : true
        }
    }
var trueFruit = Object.keys(thingsList).filter(function(key) {
    return thingsList[key];
});

return thingsList[0];

This correctly returns apples and only apples so it works for point 4 but not the others, and I feel like there is a better way to do this not having to rely on repeating the same .filter in a few different functions. Ideas?

Upvotes: 0

Views: 240

Answers (4)

user3307073
user3307073

Reputation: 

const thingsHasData = arg => (arg.things && Object.keys(arg.things).length>0) ? true : false;
const trueFruit = arg => {
    if (!arg.things) return;
    let fruitIndex = null;
    let fruitValues = Object.values(arg.things);
    fruitValues.forEach((value, index) => {
        if (value) fruitIndex = Object.keys(arg.things)[index];
    });
    return fruitIndex;
}

Upvotes: 0

Matthi
Matthi

Reputation: 1063

var thingsList = {
    things : {
        oranges: false,
        apples : true
    },
    things2 : {
        oranges: true,
        apples : true
    }
};

function validateThings(things) {
    // (1) checks for a falsy value of things
    if (!things) {
        return false;
    }
    var keys = Object.keys(things);
    // (2) checks if things has keys
    if (!keys.length) {
        return false;
    }
    // (3) then it checks for every single keys value if it is truthy
    for (var i = 0, len = keys.length; i < len; i++ ) {
        if (things[keys[i]]) {
            // (4) return this value — all tests passed
            return things[keys[i]];
        }
    }
    return false;
}

console.log(validateThings(thingsList.notInList));
console.log(validateThings(thingsList.things));
console.log(validateThings(thingsList.things2));

Upvotes: 1

Daan
Daan

Reputation: 2799

To check if the Object things exist, you can use the following code:

if (typeof things != "undefined") {
    // It exists!
}

To check if an object has any children, check Object.keys(things).length > 0.

So the check for 1) and 2) would look like:

let things = {
   oranges: true,
   apples: false
}

if (typeof things != "undefined") {
    // It exists!
    if (Object.keys(things).length > 0) {
        // It has children!
    }
}

Upvotes: 1

Nina Scholz
Nina Scholz

Reputation: 386680

You could take functions and for a true value, use Array#find.

function thingsHasData(object) {
    return 'things' in object;
}

function fruitsIsTrue(object) {
    return 'things' in object && Object.values(object.things).some(Boolean);
}

function trueFruit(object) {
    return 'things' in object && Object.keys(object.things).find(k => object.things[k]);
}

var a = {},
    b = { things: {} },
    c = { things: { oranges: true, apples : false } },
    d = { things: { oranges: false, apples : false } };

[a, b, c, d].forEach(o => console.log(
    thingsHasData(o),
    fruitsIsTrue(o),
    trueFruit(o)
));

Upvotes: 1

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