Benchmark: ETST 123123123123123

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
<script>
function stringifiable(obj) {
    // Safely stringify Object.create(null)
    /* istanbul ignore next */
    return typeof obj === 'object' && !('toString' in obj) ?
        Object.prototype.toString.call(obj).slice(8, -1) :
        obj;
}
var isProduction = typeof process === 'object' && process.env.NODE_ENV === 'production';
function invariant(condition, message) {
    if (!condition) {
        /* istanbul ignore next */
        if (isProduction) {
            throw new Error('Invariant failed');
        }
        throw new Error(message());
    }
}
var hasOwnProperty = Object.prototype.hasOwnProperty;
var splice = Array.prototype.splice;
var toString = Object.prototype.toString;
function type(obj) {
    return toString.call(obj).slice(8, -1);
}
var assign = Object.assign || /* istanbul ignore next */ (function (target, source) {
    getAllKeys(source).forEach(function (key) {
        if (hasOwnProperty.call(source, key)) {
            target[key] = source[key];
        }
    });
    return target;
});
var getAllKeys = typeof Object.getOwnPropertySymbols === 'function'
    ? function (obj) { return Object.keys(obj).concat(Object.getOwnPropertySymbols(obj)); }
    /* istanbul ignore next */
    : function (obj) { return Object.keys(obj); };
function copy(object) {
    return Array.isArray(object)
        ? assign(object.constructor(object.length), object)
        : (type(object) === 'Map')
            ? new Map(object)
            : (type(object) === 'Set')
                ? new Set(object)
                : (object && typeof object === 'object')
                    ? assign(Object.create(Object.getPrototypeOf(object)), object)
                    /* istanbul ignore next */
                    : object;
}
var Context = /** @class */ (function () {
    function Context() {
        this.commands = assign({}, defaultCommands);
        this.update = this.update.bind(this);
        // Deprecated: update.extend, update.isEquals and update.newContext
        this.update.extend = this.extend = this.extend.bind(this);
        this.update.isEquals = function (x, y) { return x === y; };
        this.update.newContext = function () { return new Context().update; };
    }
    Object.defineProperty(Context.prototype, "isEquals", {
        get: function () {
            return this.update.isEquals;
        },
        set: function (value) {
            this.update.isEquals = value;
        },
        enumerable: true,
        configurable: true
    });
    Context.prototype.extend = function (directive, fn) {
        this.commands[directive] = fn;
    };
    Context.prototype.update = function (object, $spec) {
        var _this = this;
        var spec = (typeof $spec === 'function') ? { $apply: $spec } : $spec;
        if (!(Array.isArray(object) && Array.isArray(spec))) {
            invariant(!Array.isArray(spec), function () { return "update(): You provided an invalid spec to update(). The spec may " +
                "not contain an array except as the value of $set, $push, $unshift, " +
                "$splice or any custom command allowing an array value."; });
        }
        invariant(typeof spec === 'object' && spec !== null, function () { return "update(): You provided an invalid spec to update(). The spec and " +
            "every included key path must be plain objects containing one of the " +
            ("following commands: " + Object.keys(_this.commands).join(', ') + "."); });
        var nextObject = object;
        getAllKeys(spec).forEach(function (key) {
            if (hasOwnProperty.call(_this.commands, key)) {
                var objectWasNextObject = object === nextObject;
                nextObject = _this.commands[key](spec[key], nextObject, spec, object);
                if (objectWasNextObject && _this.isEquals(nextObject, object)) {
                    nextObject = object;
                }
            }
            else {
                var nextValueForKey = type(object) === 'Map'
                    ? _this.update(object.get(key), spec[key])
                    : _this.update(object[key], spec[key]);
                var nextObjectValue = type(nextObject) === 'Map'
                    ? nextObject.get(key)
                    : nextObject[key];
                if (!_this.isEquals(nextValueForKey, nextObjectValue)
                    || typeof nextValueForKey === 'undefined'
                        && !hasOwnProperty.call(object, key)) {
                    if (nextObject === object) {
                        nextObject = copy(object);
                    }
                    if (type(nextObject) === 'Map') {
                        nextObject.set(key, nextValueForKey);
                    }
                    else {
                        nextObject[key] = nextValueForKey;
                    }
                }
            }
        });
        return nextObject;
    };
    return Context;
}());
var defaultCommands = {
    $push: function (value, nextObject, spec) {
        invariantPushAndUnshift(nextObject, spec, '$push');
        return value.length ? nextObject.concat(value) : nextObject;
    },
    $unshift: function (value, nextObject, spec) {
        invariantPushAndUnshift(nextObject, spec, '$unshift');
        return value.length ? value.concat(nextObject) : nextObject;
    },
    $splice: function (value, nextObject, spec, originalObject) {
        invariantSplices(nextObject, spec);
        value.forEach(function (args) {
            invariantSplice(args);
            if (nextObject === originalObject && args.length) {
                nextObject = copy(originalObject);
            }
            splice.apply(nextObject, args);
        });
        return nextObject;
    },
    $set: function (value, _nextObject, spec) {
        invariantSet(spec);
        return value;
    },
    $toggle: function (targets, nextObject) {
        invariantSpecArray(targets, '$toggle');
        var nextObjectCopy = targets.length ? copy(nextObject) : nextObject;
        targets.forEach(function (target) {
            nextObjectCopy[target] = !nextObject[target];
        });
        return nextObjectCopy;
    },
    $unset: function (value, nextObject, _spec, originalObject) {
        invariantSpecArray(value, '$unset');
        value.forEach(function (key) {
            if (Object.hasOwnProperty.call(nextObject, key)) {
                if (nextObject === originalObject) {
                    nextObject = copy(originalObject);
                }
                delete nextObject[key];
            }
        });
        return nextObject;
    },
    $add: function (values, nextObject, _spec, originalObject) {
        invariantMapOrSet(nextObject, '$add');
        invariantSpecArray(values, '$add');
        if (type(nextObject) === 'Map') {
            values.forEach(function (_a) {
                var key = _a[0], value = _a[1];
                if (nextObject === originalObject && nextObject.get(key) !== value) {
                    nextObject = copy(originalObject);
                }
                nextObject.set(key, value);
            });
        }
        else {
            values.forEach(function (value) {
                if (nextObject === originalObject && !nextObject.has(value)) {
                    nextObject = copy(originalObject);
                }
                nextObject.add(value);
            });
        }
        return nextObject;
    },
    $remove: function (value, nextObject, _spec, originalObject) {
        invariantMapOrSet(nextObject, '$remove');
        invariantSpecArray(value, '$remove');
        value.forEach(function (key) {
            if (nextObject === originalObject && nextObject.has(key)) {
                nextObject = copy(originalObject);
            }
            nextObject.delete(key);
        });
        return nextObject;
    },
    $merge: function (value, nextObject, _spec, originalObject) {
        invariantMerge(nextObject, value);
        getAllKeys(value).forEach(function (key) {
            if (value[key] !== nextObject[key]) {
                if (nextObject === originalObject) {
                    nextObject = copy(originalObject);
                }
                nextObject[key] = value[key];
            }
        });
        return nextObject;
    },
    $apply: function (value, original) {
        invariantApply(value);
        return value(original);
    },
};
var defaultContext = new Context();
var update = defaultContext.update;
// invariants
function invariantPushAndUnshift(value, spec, command) {
    invariant(Array.isArray(value), function () { return "update(): expected target of " + stringifiable(command) + " to be an array; got " + stringifiable(value) + "."; });
    invariantSpecArray(spec[command], command);
}
function invariantSpecArray(spec, command) {
    invariant(Array.isArray(spec), function () { return "update(): expected spec of " + stringifiable(command) + " to be an array; got " + stringifiable(spec) + ". " +
        "Did you forget to wrap your parameter in an array?"; });
}
function invariantSplices(value, spec) {
    invariant(Array.isArray(value), function () { return "Expected $splice target to be an array; got " + stringifiable(value); });
    invariantSplice(spec.$splice);
}
function invariantSplice(value) {
    invariant(Array.isArray(value), function () { return "update(): expected spec of $splice to be an array of arrays; got " + stringifiable(value) + ". " +
        "Did you forget to wrap your parameters in an array?"; });
}
function invariantApply(fn) {
    invariant(typeof fn === 'function', function () { return "update(): expected spec of $apply to be a function; got " + stringifiable(fn) + "."; });
}
function invariantSet(spec) {
    invariant(Object.keys(spec).length === 1, function () { return "Cannot have more than one key in an object with $set"; });
}
function invariantMerge(target, specValue) {
    invariant(specValue && typeof specValue === 'object', function () { return "update(): $merge expects a spec of type 'object'; got " + stringifiable(specValue); });
    invariant(target && typeof target === 'object', function () { return "update(): $merge expects a target of type 'object'; got " + stringifiable(target); });
}
function invariantMapOrSet(target, command) {
    var typeOfTarget = type(target);
    invariant(typeOfTarget === 'Map' || typeOfTarget === 'Set', function () { return "update(): " + stringifiable(command) + " expects a target of type Set or Map; got " + stringifiable(typeOfTarget); });
}
</script>

​x
 
​
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
<script>
function stringifiable(obj) {
    // Safely stringify Object.create(null)
    /* istanbul ignore next */
    return typeof obj === 'object' && !('toString' in obj) ?
        Object.prototype.toString.call(obj).slice(8, -1) :
        obj;
}
var isProduction = typeof process === 'object' && process.env.NODE_ENV === 'production';
function invariant(condition, message) {
    if (!condition) {
        /* istanbul ignore next */
        if (isProduction) {
            throw new Error('Invariant failed');
        }
        throw new Error(message());
    }
}
var hasOwnProperty = Object.prototype.hasOwnProperty;
var splice = Array.prototype.splice;
var toString = Object.prototype.toString;
function type(obj) {
    return toString.call(obj).slice(8, -1);
}
var assign = Object.assign || /* istanbul ignore next */ (function (target, source) {
    getAllKeys(source).forEach(function (key) {
        if (hasOwnProperty.call(source, key)) {
            target[key] = source[key];
        }
    });
    return target;
});
var getAllKeys = typeof Object.getOwnPropertySymbols === 'function'
    ? function (obj) { return Object.keys(obj).concat(Object.getOwnPropertySymbols(obj)); }
    /* istanbul ignore next */
    : function (obj) { return Object.keys(obj); };
function copy(object) {
    return Array.isArray(object)
        ? assign(object.constructor(object.length), object)
        : (type(object) === 'Map')
            ? new Map(object)
            : (type(object) === 'Set')
                ? new Set(object)
                : (object && typeof object === 'object')
                    ? assign(Object.create(Object.getPrototypeOf(object)), object)
                    /* istanbul ignore next */
                    : object;
}
var Context = /** @class */ (function () {
    function Context() {
        this.commands = assign({}, defaultCommands);
        this.update = this.update.bind(this);
        // Deprecated: update.extend, update.isEquals and update.newContext
        this.update.extend = this.extend = this.extend.bind(this);
        this.update.isEquals = function (x, y) { return x === y; };
        this.update.newContext = function () { return new Context().update; };
    }
    Object.defineProperty(Context.prototype, "isEquals", {
        get: function () {
            return this.update.isEquals;
        },
        set: function (value) {
            this.update.isEquals = value;
        },
        enumerable: true,
        configurable: true
    });
    Context.prototype.extend = function (directive, fn) {
        this.commands[directive] = fn;
    };
    Context.prototype.update = function (object, $spec) {
        var _this = this;
        var spec = (typeof $spec === 'function') ? { $apply: $spec } : $spec;
        if (!(Array.isArray(object) && Array.isArray(spec))) {
            invariant(!Array.isArray(spec), function () { return "update(): You provided an invalid spec to update(). The spec may " +
                "not contain an array except as the value of $set, $push, $unshift, " +
                "$splice or any custom command allowing an array value."; });
        }
        invariant(typeof spec === 'object' && spec !== null, function () { return "update(): You provided an invalid spec to update(). The spec and " +
            "every included key path must be plain objects containing one of the " +
            ("following commands: " + Object.keys(_this.commands).join(', ') + "."); });
        var nextObject = object;
        getAllKeys(spec).forEach(function (key) {
            if (hasOwnProperty.call(_this.commands, key)) {
                var objectWasNextObject = object === nextObject;
                nextObject = _this.commands[key](spec[key], nextObject, spec, object);
                if (objectWasNextObject && _this.isEquals(nextObject, object)) {
                    nextObject = object;
                }
            }
            else {
                var nextValueForKey = type(object) === 'Map'
                    ? _this.update(object.get(key), spec[key])
                    : _this.update(object[key], spec[key]);
                var nextObjectValue = type(nextObject) === 'Map'
                    ? nextObject.get(key)
                    : nextObject[key];
                if (!_this.isEquals(nextValueForKey, nextObjectValue)
                    || typeof nextValueForKey === 'undefined'
                        && !hasOwnProperty.call(object, key)) {
                    if (nextObject === object) {
                        nextObject = copy(object);
                    }
                    if (type(nextObject) === 'Map') {
                        nextObject.set(key, nextValueForKey);
                    }
                    else {
                        nextObject[key] = nextValueForKey;
                    }
                }
            }
        });
        return nextObject;
    };
    return Context;
}());
var defaultCommands = {
    $push: function (value, nextObject, spec) {
        invariantPushAndUnshift(nextObject, spec, '$push');
        return value.length ? nextObject.concat(value) : nextObject;
    },
    $unshift: function (value, nextObject, spec) {
        invariantPushAndUnshift(nextObject, spec, '$unshift');
        return value.length ? value.concat(nextObject) : nextObject;
    },
    $splice: function (value, nextObject, spec, originalObject) {
        invariantSplices(nextObject, spec);
        value.forEach(function (args) {
            invariantSplice(args);
            if (nextObject === originalObject && args.length) {
                nextObject = copy(originalObject);
            }
            splice.apply(nextObject, args);
        });
        return nextObject;
    },
    $set: function (value, _nextObject, spec) {
        invariantSet(spec);
        return value;
    },
    $toggle: function (targets, nextObject) {
        invariantSpecArray(targets, '$toggle');
        var nextObjectCopy = targets.length ? copy(nextObject) : nextObject;
        targets.forEach(function (target) {
            nextObjectCopy[target] = !nextObject[target];
        });
        return nextObjectCopy;
    },
    $unset: function (value, nextObject, _spec, originalObject) {
        invariantSpecArray(value, '$unset');
        value.forEach(function (key) {
            if (Object.hasOwnProperty.call(nextObject, key)) {
                if (nextObject === originalObject) {
                    nextObject = copy(originalObject);
                }
                delete nextObject[key];
            }
        });
        return nextObject;
    },
    $add: function (values, nextObject, _spec, originalObject) {
        invariantMapOrSet(nextObject, '$add');
        invariantSpecArray(values, '$add');
        if (type(nextObject) === 'Map') {
            values.forEach(function (_a) {
                var key = _a[0], value = _a[1];
                if (nextObject === originalObject && nextObject.get(key) !== value) {
                    nextObject = copy(originalObject);
                }
                nextObject.set(key, value);
            });
        }
        else {
            values.forEach(function (value) {
                if (nextObject === originalObject && !nextObject.has(value)) {
                    nextObject = copy(originalObject);
                }
                nextObject.add(value);
            });
        }
        return nextObject;
    },
    $remove: function (value, nextObject, _spec, originalObject) {
        invariantMapOrSet(nextObject, '$remove');
        invariantSpecArray(value, '$remove');
        value.forEach(function (key) {
            if (nextObject === originalObject && nextObject.has(key)) {
                nextObject = copy(originalObject);
            }
            nextObject.delete(key);
        });
        return nextObject;
    },
    $merge: function (value, nextObject, _spec, originalObject) {
        invariantMerge(nextObject, value);
        getAllKeys(value).forEach(function (key) {
            if (value[key] !== nextObject[key]) {
                if (nextObject === originalObject) {
                    nextObject = copy(originalObject);
                }
                nextObject[key] = value[key];
            }
        });
        return nextObject;
    },
    $apply: function (value, original) {
        invariantApply(value);
        return value(original);
    },
};
var defaultContext = new Context();
var update = defaultContext.update;
// invariants
function invariantPushAndUnshift(value, spec, command) {
    invariant(Array.isArray(value), function () { return "update(): expected target of " + stringifiable(command) + " to be an array; got " + stringifiable(value) + "."; });
    invariantSpecArray(spec[command], command);
}
function invariantSpecArray(spec, command) {
    invariant(Array.isArray(spec), function () { return "update(): expected spec of " + stringifiable(command) + " to be an array; got " + stringifiable(spec) + ". " +
        "Did you forget to wrap your parameter in an array?"; });
}
function invariantSplices(value, spec) {
    invariant(Array.isArray(value), function () { return "Expected $splice target to be an array; got " + stringifiable(value); });
    invariantSplice(spec.$splice);
}
function invariantSplice(value) {
    invariant(Array.isArray(value), function () { return "update(): expected spec of $splice to be an array of arrays; got " + stringifiable(value) + ". " +
        "Did you forget to wrap your parameters in an array?"; });
}
function invariantApply(fn) {
    invariant(typeof fn === 'function', function () { return "update(): expected spec of $apply to be a function; got " + stringifiable(fn) + "."; });
}
function invariantSet(spec) {
    invariant(Object.keys(spec).length === 1, function () { return "Cannot have more than one key in an object with $set"; });
}
function invariantMerge(target, specValue) {
    invariant(specValue && typeof specValue === 'object', function () { return "update(): $merge expects a spec of type 'object'; got " + stringifiable(specValue); });
    invariant(target && typeof target === 'object', function () { return "update(): $merge expects a target of type 'object'; got " + stringifiable(target); });
}
function invariantMapOrSet(target, command) {
    var typeOfTarget = type(target);
    invariant(typeOfTarget === 'Map' || typeOfTarget === 'Set', function () { return "update(): " + stringifiable(command) + " expects a target of type Set or Map; got " + stringifiable(typeOfTarget); });
}
</script>
​

Script Preparation code:

var myArr = Array.from({
    length: 1_000_000
}, () => ({ id: Math.floor(Math.random() * 1000) }));

var myArr2 = Array.from({
    length: 1_000_000
}, () => ({ id: Math.floor(Math.random() * 1000) }));


var myCopy = null;

 
var myArr = Array.from({    length: 1_000_000}, () => ({ id: Math.floor(Math.random() * 1000) }));​var myArr2 = Array.from({    length: 1_000_000}, () => ({ id: Math.floor(Math.random() * 1000) }));​​var myCopy = null;

Tests:

uniqBy
myCopy = _.uniqBy([...myArr, ...myArr2], 'id');
myCopy = _.uniqBy([...myArr, ...myArr2], 'id');

Set with filter

myCopy = (() => {
    const existingIds = new Set(myArr.map((machine) => machine.id));
    const newMachines = myArr2.filter((machine) => !existingIds.has(machine.id));

    return update(myArr, {
        $push: newMachines,
    });
})();

 
myCopy = (() => {    const existingIds = new Set(myArr.map((machine) => machine.id));    const newMachines = myArr2.filter((machine) => !existingIds.has(machine.id));​    return update(myArr, {        $push: newMachines,    });})();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
uniqBy
Set with filter

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/133.0.0.0 Safari/537.36

Browser/OS: Chrome 133 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
uniqBy	25.7 Ops/sec
Set with filter	16.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

The provided benchmark compares two approaches to deduplicate an array of objects based on a specific property (id): one using the Lodash library's _.uniqBy method, and the other using a native JavaScript approach that leverages Set and the filter method.

Approaches Compared

Lodash's _.uniqBy Method
- Code: myCopy = _.uniqBy([...myArr, ...myArr2], 'id');
- Description: This method combines myArr and myArr2 into a new array and then deduplicates it by the id property of the objects in the array.
- Pros:
  - Simplicity: The syntax is straightforward and easy to read, making it clear that we are trying to find unique items based on a specific property.
  - Performance: Lodash is highly optimized for performance and handles common cases efficiently.
- Cons:
  - Dependency: This approach requires including the Lodash library, which increases the bundle size if used in a frontend application.
  - Performance Overhead: For very large arrays, Lodash's internal operations may introduce some performance overhead compared to more optimized native solutions.
Set with Filter
- Code:
```
myCopy = (() => {
    const existingIds = new Set(myArr.map((machine) => machine.id));
    const newMachines = myArr2.filter((machine) => !existingIds.has(machine.id));
    return update(myArr, { $push: newMachines });
})();
```
- Description: This approach first extracts all existing ids from myArr into a Set, then filters myArr2 to exclude any items with ids already present in the set, and finally adds the filtered items to myArr.
- Pros:
  - Native Solution: Utilizes built-in JavaScript features like Set and Array.prototype.filter, avoiding the need for an external library.
  - Efficiency for Lookup: Checking if an id is in a Set is generally O(1) on average, which can lead to improved performance for certain datasets.
- Cons:
  - Complexity: The approach is less straightforward than using Lodash, as it involves multiple steps including mapping, filtering, and updating, which can lead to less readable code.
  - Overhead for Updates: The use of update (presumably a custom function) adds complexity. It may introduce its own performance costs depending on how it has been implemented.

Benchmark Results

The benchmark results indicate:

uniqBy: 25.74 executions per second.
Set with filter: 16.00 executions per second.

The performance measurements show that Lodash's uniqBy method performs better than the custom Set and filter approach in this case.

Other Considerations

Alternatives: In addition to the two methods described, there are other approaches to achieve similar deduplication:

Using an object map: Create a temporary object to track seen ids, which can be faster than using a Set in certain cases:

const seen = {};
const result = [...myArr, ...myArr2].filter(item => {
    if (seen[item.id]) {
        return false;
    } else {
        seen[item.id] = true;
        return true;
    }
});

Using reduce: Perform deduplication in a single pass:

const result = [...myArr, ...myArr2].reduce((acc, item) => {
    if (!acc.find(i => i.id === item.id)) {
        acc.push(item);
    }
    return acc;
}, []);

Conclusion

In scenarios requiring deduplication in JavaScript, both Lodash's _.uniqBy and native Set with filter are viable options. Each approach has its pros and cons, and the decision may depend on the specific use case, performance considerations, and code readability preferences. Additionally, examining alternative methods can provide further optimization opportunities, especially when avoiding external library dependencies is a priority.

LLMs can make mistakes. Check important info.

The provided benchmark compares two approaches to deduplicate an array of objects based on a specific property (`id`): one using the Lodash library's `_.uniqBy` method, and the other using a native JavaScript approach that leverages `Set` and the `filter` method.

### Approaches Compared

1. **Lodash's `_.uniqBy` Method**
   - **Code**: `myCopy = _.uniqBy([...myArr, ...myArr2], 'id');`
   - **Description**: This method combines `myArr` and `myArr2` into a new array and then deduplicates it by the `id` property of the objects in the array.
   - **Pros**:
     - **Simplicity**: The syntax is straightforward and easy to read, making it clear that we are trying to find unique items based on a specific property.
     - **Performance**: Lodash is highly optimized for performance and handles common cases efficiently.
   - **Cons**:
     - **Dependency**: This approach requires including the Lodash library, which increases the bundle size if used in a frontend application.
     - **Performance Overhead**: For very large arrays, Lodash's internal operations may introduce some performance overhead compared to more optimized native solutions.

2. **Set with Filter**
   - **Code**: 
     ```javascript
     myCopy = (() => {
         const existingIds = new Set(myArr.map((machine) => machine.id));
         const newMachines = myArr2.filter((machine) => !existingIds.has(machine.id));
         return update(myArr, { $push: newMachines });
     })();
     ```
   - **Description**: This approach first extracts all existing `id`s from `myArr` into a `Set`, then filters `myArr2` to exclude any items with `id`s already present in the set, and finally adds the filtered items to `myArr`.
   - **Pros**:
     - **Native Solution**: Utilizes built-in JavaScript features like `Set` and `Array.prototype.filter`, avoiding the need for an external library.
     - **Efficiency for Lookup**: Checking if an `id` is in a `Set` is generally O(1) on average, which can lead to improved performance for certain datasets.
   - **Cons**:
     - **Complexity**: The approach is less straightforward than using Lodash, as it involves multiple steps including mapping, filtering, and updating, which can lead to less readable code.
     - **Overhead for Updates**: The use of `update` (presumably a custom function) adds complexity. It may introduce its own performance costs depending on how it has been implemented.

### Benchmark Results
The benchmark results indicate:
- **`uniqBy`**: 25.74 executions per second.
- **`Set with filter`**: 16.00 executions per second.

The performance measurements show that Lodash's `uniqBy` method performs better than the custom `Set` and `filter` approach in this case.

### Other Considerations
- **Alternatives**: In addition to the two methods described, there are other approaches to achieve similar deduplication:
  - **Using an object map**: Create a temporary object to track seen ids, which can be faster than using a `Set` in certain cases:
    ```javascript
    const seen = {};
    const result = [...myArr, ...myArr2].filter(item => {
        if (seen[item.id]) {
            return false;
        } else {
            seen[item.id] = true;
            return true;
        }
    });
    ```
  - **Using `reduce`**: Perform deduplication in a single pass:
    ```javascript
    const result = [...myArr, ...myArr2].reduce((acc, item) => {
        if (!acc.find(i => i.id === item.id)) {
            acc.push(item);
        }
        return acc;
    }, []);
    ```

### Conclusion
In scenarios requiring deduplication in JavaScript, both Lodash's `_.uniqBy` and native `Set` with `filter` are viable options. Each approach has its pros and cons, and the decision may depend on the specific use case, performance considerations, and code readability preferences. Additionally, examining alternative methods can provide further optimization opportunities, especially when avoiding external library dependencies is a priority.

Related benchmarks:

ETST 123123123123123 (version: 1)

Lodash uniqBy vs [...new Set()]

Comparing performance of: uniqBy vs Set with filter

Created: one month ago by: Guest

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uniqBy