28 JavaScript One-Liners every Senior Developer Needs to Know

1. Swapping Values Without a Temporary Variable

let a = 1, b = 2;

[a, b] = [b, a];

// Output: a = 2, b = 1

This one-liner uses array destructuring to swap the values of a and b without needing a temporary variable. It's a neat trick that makes your code cleaner and more concise. The [a, b] = [b, a] syntax swaps their values by destructuring the array on the right-hand side and assigning it to the left-hand side.

2. Object Destructuring for Easier Data Access

const {name, age} = {name: 'John', age: 30};

// Output: name = 'John', age = 30

Here, object destructuring is used to extract name and age properties from an object directly into variables. This approach simplifies accessing object properties and enhances code readability.

3. Cloning Objects in a Snap

const originalObj = {name: 'Jane', age: 22};

const clonedObj = {...originalObj};

// Output: clonedObj = {name: 'Jane', age: 22}

The spread operator (...) is utilized to create a shallow clone of originalObj. This technique copies all enumerable own properties from the original object to a new object.

So can we not simply assign the old object to the new one?

const clonedObj = originalObj;
clonedObj.name = "George";

// Output: originalObj = {name: 'George', age: 22}

You can do this but clonedObj will simply be a reference to originalObj so if you tried modifying the name property on clonedObj you will actually be modifying the originalObj!

4. Merging Objects Made Simple

const obj1 = {name: 'Jane'};
const obj2 = {age: 22};

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

// Output: mergedObj = {name: 'Jane', age: 22}

Similar to cloning, the spread operator is used to merge obj1 and obj2 into a new object. If there are overlapping properties, the properties from the last object will override the previous ones.

5. Cleaning Up Arrays

const arr = [0, 1, false, 2, '', 3];

const…