JavaScript - equivalent to C#/.NET LINQ's Enumerable.First(predicate)

Try to use Array findIndex(condition).

Here's an example of an arrow function that should work the same way as LINQ's First() method:

// ONLINE-RUNNER:browser;

const firstItem = (array, condition = () => true) => {
    const index = array.findIndex(condition);
    if (index === -1) {
        throw new Error('Item is not available.');
    }
    return array[index];
};


// Usage example:

const array = ['a', 'b', 'c', null, undefined];

const item1 = firstItem(array);
const item2 = firstItem(array, (item) => item === 'b');
const item3 = firstItem(array, (item) => item === null);
const item4 = firstItem(array, (item) => item === undefined);
//            firstItem(array, (item) => item === 'z');  // it throws exception like C# method

console.log(item1); // a
console.log(item2); // b
console.log(item3); // null
console.log(item4); // undefined

References

1. Array.prototype.findIndex() - JavaScript | MDN
2. Enumerable.First Method (System.Linq) | Microsoft Docs