remove-duplicates-objects-from-array.js

let arr = [
    {
        firstName: 'Jon',
        lastName: 'Doe'
    },
    {
        firstName: 'example',
        lastName: 'example'
    },
    {
        firstName: 'Jon',
        lastName: 'Doe'
    }
];

const removeDuplicates = (arr) => {

    const SymbolArray = [];
    arr.forEach((item, index) => {
        const {firstName, lastName} = item;
        let keyStr = `${firstName}_${lastName}`;
        SymbolArray.push(Symbol.for(keyStr));
    });

    const results = [];
    SymbolArray.forEach((item, index) => {
        if(SymbolArray.indexOf(item) === index) {
            results.push(arr[index]);
        }
    });

    return results;
}