25 lines
1.2 KiB
Markdown
25 lines
1.2 KiB
Markdown
### equals
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Performs a deep comparison between two values to determine if they are equivalent.
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Check if the two values are identical, if they are both `Date` objects with the same time, using `Date.getTime()` or if they are both non-object values with an equivalent value (strict comparison).
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Check if only one value is `null` or `undefined` or if their prototypes differ.
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If none of the above conditions are met, use `Object.keys()` to check if both values have the same number of keys, then use `Array.every()` to check if every key in the first value exists in the second one and if they are equivalent by calling this method recursively.
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```js
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const equals = (a, b) => {
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if (a === b) return true;
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if (a instanceof Date && b instanceof Date) return a.getTime() === b.getTime();
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if (!a || !b || (typeof a != 'object' && typeof b !== 'object')) return a === b;
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if (a === null || a === undefined || b === null || b === undefined) return false;
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if (a.prototype !== b.prototype) return false;
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let keys = Object.keys(a);
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if (keys.length !== Object.keys(b).length) return false;
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return keys.every(k => equals(a[k], b[k]));
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};
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```
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```js
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equals({ a: [2, { e: 3 }], b: [4], c: 'foo' }, { a: [2, { e: 3 }], b: [4], c: 'foo' }); // true
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```
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