Tips & Tricks

Programming Popular

Use Array.includes() for Multiple Conditions

Problem

Checking multiple OR conditions creates long, repetitive comparison chains.

Solution

Use Array.includes() to check if a value matches any item in an array of possibilities.

Benefit

Reduces condition complexity by 70% and makes code more maintainable.

Code Example Read tip

Math

Multiply Two 2-Digit Numbers Ending in Same Digit

Problem

Multiplying numbers like 23×27 or 41×49 requires full multiplication.

Solution

When tens digit is same and ones add to 10: Multiply tens×(tens+1), then ones×ones.

Benefit

Special case shortcut that saves 80% of calculation time.

Example Read tip

Programming Popular

Use Optional Chaining for Nested Properties

Problem

Accessing deeply nested object properties requires multiple null/undefined checks.

Solution

Use optional chaining (?.) to safely access nested properties without explicit null checks.

Benefit

Eliminates 90% of null checking code and prevents "Cannot read property" errors.

Code Example Read tip

Math

Add Fractions with Different Denominators

Problem

Adding fractions requires finding least common denominator which is time-consuming.

Solution

Use cross-multiplication: (a/b + c/d) = (ad + bc) / (bd)

Benefit

Universal method that works for any fraction addition without finding LCD.

Example Read tip

Programming Popular

Use Array.find() Instead of filter()[0]

Problem

Using filter() to find a single item processes the entire array unnecessarily.

Solution

Use Array.find() which stops at the first match, improving performance.

Benefit

Up to 100x faster for large arrays and makes intent clearer.

Code Example Read tip

Math

Multiply by 99 Trick

Problem

Multiplying by 99 requires long multiplication with carrying.

Solution

Multiply by 100 and subtract the original number.

Benefit

Converts difficult multiplication into simple subtraction.

Example Read tip

Programming Popular

Use Set to Remove Array Duplicates

Problem

Removing duplicates from arrays requires nested loops or complex filter logic.

Solution

Convert array to Set (which only stores unique values) then back to array.

Benefit

One-line solution that is 50x faster than traditional approaches.

Code Example Read tip

Math Popular

Calculate Tip Percentage Quickly

Problem

Calculating 15% or 20% tips at restaurants requires mental math under pressure.

Solution

10% = move decimal left. 20% = double that. 15% = 10% + half of 10%.

Benefit

Calculate common tip percentages in 3 seconds without calculator.

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