Small Ideas That Solve Real Problems

Measuring code execution time requires manual Date.now() calculations.

Use console.time() and console.timeEnd() to measure execution time easily.

Simple, accurate performance measurement without manual timestamp math.

Adding long lists of numbers one at a time is slow and error-prone.

Look for pairs that sum to 10, group numbers that are easy to add (like 25+75=100).

Speeds up mental addition by 50% by reducing the number of operations.

Debugging arrays of objects with console.log() produces hard-to-read nested output that requires expanding each item.

Use console.table() to display arrays and objects in a clean, sortable table format in your browser DevTools.

Instantly see all data in a structured table — sortable by column, easy to scan, no expanding needed.

Calculating how long it takes for an investment to double at a given interest rate requires compound interest formulas.

Divide 72 by the annual interest rate to get the approximate number of years to double your money.

Instant mental calculation for financial planning — no calculator or compound interest formula needed.

Boolean variables named "active", "permission", or "valid" are ambiguous — is it a status, a check, or an action?

Prefix booleans with is, has, can, should, or was. They read like questions: isActive, hasPermission, canEdit.

Code reads like English. "if (isActive && hasPermission)" is instantly understandable vs "if (active && permission)".

Some percentage calculations like "8% of 50" are harder to compute mentally than their flipped equivalent.

X% of Y = Y% of X. Always flip to whichever is easier. 8% of 50 = 50% of 8 = 4.

Turns difficult percentage problems into trivial ones — works every time because multiplication is commutative.

Code like "if (status === 3)" or "timeout = 86400" is meaningless to anyone reading it — including your future self.

Replace magic numbers with named constants. The name explains the purpose, and changing the value only requires one edit.

Self-documenting code, fewer bugs when values change, and easier code reviews.

Squaring numbers like 35, 65, or 85 requires long multiplication that is slow and error-prone.

Take the tens digit, multiply it by (itself + 1), then append 25 at the end. Done.

Square any number ending in 5 in under 3 seconds mentally — no pen, paper, or calculator needed.