How can I determine equality for two JavaScript objects?

Tap into lodash: a developer's Swiss-knife

Lodash's _.isEqual function is like that all-knowing friend who never fails to surprise you. It provides a robust solution for deep object comparisons. Borrow the wisdom:

const isEqual = require('lodash').isEqual(obj1, obj2);
// Lodash: Because you have better things to do than reinvent solutions


It's like comparing DNAs, even the most deeply nested genes don't escape lodash's scrutiny.

Roll your own: object-specific comparison

Sometimes, you need a custom equals(other) method. You define the rules of the game:

class MyObject {
  constructor(data) {
    this.data = data;  // It's a constructor, not a deconstructor
  }

  equals(other) {
    // DIY comparison logic, you're the boss here!
    return deepEqual(this.data, other.data);
  }
}
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Navigating edge cases: functions, regex, dates, arrays

Special objects need special attention:

• Date Objects: In the world of dates, it's the timestamp that counts, not the fancy formatting!
• Functions: Sorry functions, you're out of the comparison game, too complex to handle.
• Arrays: Special creatures but still objects, treat accordingly.

// It's a date...or is it?
if (obj1 instanceof Date && obj2 instanceof Date) {
  equals = obj1.valueOf() === obj2.valueOf();  // Check their timestamps, not their outfits
}

// Oh look, arrays wanna play too!
equals = Array.isArray(obj1) && Array.isArray(obj2) &&
         obj1.length === obj2.length &&
         obj1.every((value, index) => deepEqual(value, obj2[index]));  // No child(left) behind!
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ABA: Always Be Adapting with ES6 features

Modern JavaScript is your friend. Destructuring, spread, Arrow functions makes your code concise and understandable:

const deepEqual = (a, b) => {  // Naughty or nice, they're all the same to me!
  if (a === b) return true;
  if (a && b && typeof a === 'object' && typeof b === 'object') {
    let keys = [Object.keys(a), Object.keys(b)];
    // Because order and details matter in a heist...err...comparison!
    return keys[0].every(key => keys[1].includes(key) && deepEqual(a[key], b[key]));
  }
  return false;
};
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Bring out the big guns: lodash for comparison

When the going gets tough, the tough get lodash. Comparing nested objects? Check. Bugs? Squashed. Say hello to reliability and goodbye to redundancies!

const _ = require('lodash');
const isEqual = _.isEqual(object1, object2);
// Who needs Sherlock when you've got Lodash?


Invoke the lodash's _.isEqual for maximum precision and minimum effort.

Build for resilience: handle edge cases

You're on a quest for truth. Be prepared to tackle special object types (Dates, Arrays, Functions, Regex). For each, there's a unique path to truth:

• Dates: Use valueOf to check timestamp equality.
• Arrays: They are objects too! Use object comparison.
• Functions: Often omitted due to complexity of comparing behaviors.
• Regular expressions: Convert to string before comparison.