Tips & Tricks

Programming

Use Object.keys() to Check Empty Objects

Problem

Checking if an object is empty requires iterating through its properties manually.

Solution

Use Object.keys(obj).length === 0 to quickly check if an object has no properties.

Benefit

One-line solution that is faster and more reliable than manual iteration.

Code Example Read tip

Math Popular

Quick Percentage Calculation

Problem

Calculating percentages like 15% or 18% requires complex mental math.

Solution

Break percentages into easy parts: 10%, 5%, 1%. Then combine them.

Benefit

Calculate any percentage mentally by breaking it into simple components.

Example Read tip

Programming

Use Array.filter() to Remove Falsy Values

Problem

Removing null, undefined, 0, false, NaN from arrays requires complex conditional logic.

Solution

Use Array.filter(Boolean) to remove all falsy values in one line.

Benefit

Eliminates 10+ lines of conditional logic and handles all falsy values automatically.

Code Example Read tip

Math

Divisibility Rule for 3

Problem

Testing if large numbers are divisible by 3 requires actual division.

Solution

Sum all digits. If the sum is divisible by 3, the number is divisible by 3.

Benefit

Instant divisibility test without performing division.

Example Read tip

Programming Popular

Use Default Parameters

Problem

Functions need fallback values when parameters are not provided, requiring manual checks.

Solution

Use default parameter syntax to automatically assign fallback values in function signatures.

Benefit

Reduces defensive coding by 50% and makes function interfaces self-documenting.

Code Example Read tip

Math

Divisibility Rule for 9

Problem

Checking divisibility by 9 for large numbers requires long division.

Solution

Sum all digits. If the sum is divisible by 9, the number is divisible by 9.

Benefit

Quick mental check for divisibility by 9 without calculation.

Example Read tip

Programming Popular

Use Spread Operator to Clone Arrays

Problem

Copying arrays with traditional methods can accidentally create references instead of new arrays.

Solution

Use the spread operator [...arr] to create a shallow copy of an array.

Benefit

Prevents mutation bugs and creates independent copies in one simple syntax.

Code Example Read tip

Math

Fast Square Root Estimation

Problem

Finding square roots mentally for non-perfect squares is difficult.

Solution

Find the two perfect squares it falls between, then estimate proportionally.

Benefit

Get accurate estimates (±0.5) of square roots mentally in seconds.

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