find document which is not in array

Finding a document which is not in an array can be achieved in various ways. It all depends on the context of the array and the document you are attempting to find.

If you know the format of the document you are looking for, then you can use the Array.prototype.includes() method. This method will search through the array and return a boolean value indicating whether or not the document is present. For example:

const array = ['doc1', 'doc2', 'doc3'];
const document = 'doc4';

if (array.includes(document)) {
    console.log('Document found!');
} else {
    console.log('Document not found.');
}

If you don't know the format of the document you are looking for, but know that it should not be present in the array, then you can use the Array.prototype.indexOf() method. This method searches the array and returns the index of the document if it is present. If the document is not present, it will return a -1. For example:

const array = ['doc1', 'doc2', 'doc3'];
const document = 'doc4';

if (array.indexOf(document) !== -1) {
    console.log('Document found!');
} else {
    console.log('Document not found.');
}

Finally, if you are working with objects in the array, you can use the Array.prototype.find() method. This method searches the array for an element that satisfies the provided condition. Once found, it will return the element. If no element satisfying the condition is found, it will return undefined. For example:

const array = [{name: 'doc1'}, {name: 'doc2'}, {name: 'doc3'}];
const document = {name: 'doc4'};

const found = array.find(el => el.name === document.name);

if (found) {
    console.log('Document found!');
} else {
    console.log('Document not found.');
}

These are just a few of the ways you can find a document which is not in an array. It all depends on the context of the array and the document you are attempting to find. I hope this helps!