10 One‑Line JavaScript Tricks to Simplify Everyday Coding

In JavaScript development we often encounter seemingly complex problems that can be solved with concise code. Below are ten one‑line JavaScript tricks that address common challenges.

1. Array deduplication

const uniqueArray = [...new Set(array)];

This line uses the uniqueness of Set to deduplicate an array in a single step, more concise and efficient than traditional loops.

2. Convert object property values to array

const values = Object.values(object);

Directly obtains all property values of an object and converts them into an array, avoiding manual iteration.

3. Generate random boolean

const randomBoolean = Math.random() >= 0.5;

Creates a random boolean value, useful for decisions that require randomness.

4. Get random element from array

const randomElement = array[Math.floor(Math.random() * array.length)];

Selects a random element from an array, suitable for lotteries, random displays, etc.

5. Check if variable is null or undefined

const isNullOrUndefined = value == null;

Checks whether a variable is null or undefined, simplifying conditional checks.

6. Convert string to number

const num = +"42";

Uses the unary plus operator to quickly convert a string to a number, more concise than parseInt().

7. Round to specific decimal places

const toFixed = num => Math.round(num * 100) / 100; // keep two decimals

A more reliable method than toFixed() for retaining decimal places, avoiding rounding issues.

8. Merge objects

const mergedObject = {...obj1, ...obj2};

Uses the spread operator to quickly merge multiple objects; later properties overwrite earlier ones with the same name.

9. Get URL parameters

const params = Object.fromEntries(new URLSearchParams(window.location.search));

Parses query parameters from the URL in one line, returning an object containing all parameters.

10. Deep copy an object

const deepCopy = JSON.parse(JSON.stringify(object));

Although limited (cannot handle functions or circular references), this is the simplest deep‑copy method for most JSON‑compatible data structures.