Logical assignment operators combine logical operations with assignment for cleaner code. Here's how to use them.
Nullish Coalescing Assignment (??=)
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Logical OR Assignment (||=)
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Logical AND Assignment (&&=)
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Object Property Defaults
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Function Parameters
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Lazy Initialization
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Array Operations
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State Management
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DOM Manipulation
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API Response Handling
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Comparison Table
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Best Practices
Usage:
✓ ??= for null/undefined defaults
✓ ||= for falsy defaults
✓ &&= for conditional updates
✓ Initialize object properties
Patterns:
✓ Lazy initialization
✓ Cache population
✓ Default parameters
✓ Object property defaults
Prefer ??= when:
✓ 0 is a valid value
✓ '' is a valid value
✓ false is a valid value
✓ Only null/undefined should trigger
Avoid:
✗ Complex chaining
✗ Side effects in right-hand side
✗ Confusion with similar operators
✗ Overusing when simple = works
Conclusion
Logical assignment operators provide concise syntax for conditional assignments. Use ??= when only null or undefined should trigger assignment, ||= when any falsy value should trigger, and &&= when you want to replace truthy values. They're particularly useful for setting defaults, lazy initialization, and normalizing data.