How can I skip to value to specific key in JSON object?

November 8, 2021

So I am dealing with an object that looks a bit like this:

{
  examples: [
    { key: 'value1' },
    { key: 'value1' },
    { key: 'value1' },
    { key: 'value2' },
    { key: 'value2' },
    { key: 'value2' }
  ]
}

As you can see the values are ordered. I’m trying to get where the value is value2 and I’m sure there is a more efficient way than what I am doing currently, as the actual object is significantly larger and so it takes some time to reach value2.
This is the function I created:

function getValue2 (obj, num) {
    if (obj.examples[num] = "value2"){
        console.log(obj.examples[num]);
    }
    else {
        getValue2(obj, num + 1);
    };
};

var x = JSON.parse(obj);
getValue2(x, 0);

Thank you in advance! 🙂

>Solution :

You can use Array#find:

returns the value of the first element in the provided array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned.

const data = {
  examples: [ { key: 'value1' }, { key: 'value1' }, { key: 'value1' }, { key: 'value2' }, { key: 'value2' }, { key: 'value2' } ]
};

const res = data.examples.find(({ key }) => key === 'value2');

console.log(res);

To get the index of the first occurrence, you can use Array#findIndex:

returns the index of the first element in the array that satisfies the provided testing function. Otherwise, it returns -1, indicating that no element passed the test.

const data = {
  examples: [ { key: 'value1' }, { key: 'value1' }, { key: 'value1' }, { key: 'value2' }, { key: 'value2' }, { key: 'value2' } ]
};

const index = data.examples.findIndex(({ key }) => key === 'value2');

console.log(index);