Section 1.1: Extracting Unique Values from Arrays

To eliminate duplicate values from an array, you can leverage the Set object. Here's how to retrieve unique numbers from an array:

const numbers = [1, 1, 2, 3, 4, 4, 5];

const uniqueNumbers = [...new Set(numbers)];

console.log(uniqueNumbers); // Output: [1, 2, 3, 4, 5]

The Spread operator (...) is utilized here to include all elements from the numbers array.

Section 1.2: Converting Numbers to Strings

There are multiple ways to convert numbers to strings in JavaScript:

let a = 2;

let s1 = a.toString();

let s2 = String(a);

let s3 = '' + a;

let s4 = ${a};

console.log(s1, typeof s1); // Output: 2 string

console.log(s2, typeof s2); // Output: 2 string

console.log(s3, typeof s3); // Output: 2 string

console.log(s4, typeof s4); // Output: 2 string

Any of these methods can be used to convert numeric values, but concatenating with an empty string is often the simplest.

Explore additional JavaScript hacks that you may not be familiar with in this insightful video.

Section 1.3: Transforming Strings to Numbers

To convert strings into numbers, you can use the + operator:

const toNumber = (str) => (+str);

console.log(toNumber('test')); // Output: NaN

console.log(toNumber('3')); // Output: 3

console.log(toNumber(new Date())); // Output: 1671598549947

Alternatively, the double tilde operator (~~) can also be employed:

console.log(~~('test')); // Output: 0

console.log(~~('3')); // Output: 3

If the string cannot be converted, it will return NaN, while non-numeric strings yield 0.

Section 1.4: Streamlining Conditional Statements

You can simplify conditional statements using the logical AND (&&) and OR (||) operators:

// Standard method

if (someCondition) {

console.log("I'm in");

}

// Concise method

someCondition && console.log("I'm in"); // Output: I'm in

// Standard method

if (data) {

return data;

} else {

return 'no data';

}

// Concise method

return (data || 'no data');

Section 2.1: Setting Default Values

You can define default values in function parameters using the OR operator:

function Car(make, year) {

this.make = make || 'Toyota';

this.year = year || 2000;

}

let carOne = new Car('Ford', 1998);

console.log(carOne.make, carOne.year); // Output: Ford 1998

let carTwo = new Car();

console.log(carTwo.make, carTwo.year); // Output: Toyota 2000

This method allows for fallback values when parameters are not provided.

Section 2.2: Resizing and Emptying Arrays

You can adjust the size of an array or clear its contents by manipulating its length property:

let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9];

console.log(numbers.length); // Output: 9

// Resize the array

numbers.length = 4;

console.log(numbers, numbers.length); // Output: [1, 2, 3, 4] 4

// Empty the array

numbers.length = 0;

console.log(numbers, numbers.length); // Output: [] 0

Section 2.3: Merging Arrays

You can combine arrays using Array.concat() or Array.push.apply():

// For smaller arrays

let first = [1, 2, 3, 4, 5];

let second = ['a', 'e', 'i', 'o', 'u'];

console.log(first.concat(second)); // Output: [1, 2, 3, 4, 5, 'a', 'e', 'i', 'o', 'u']

// For larger arrays

console.log(first.push.apply(first, second)); // Output: 10

console.log(first); // Output: [1, 2, 3, 4, 5, 'a', 'e', 'i', 'o', 'u']

For larger datasets, Array.push.apply() is more memory-efficient.

Section 2.4: Boolean Conversion

To convert any value to a boolean, you can use the double negation operator (!!):

const thanks = "Thanks for reading!";

console.log(!!thanks); // Output: true

console.log(Boolean(thanks)); // Output: true

This method returns false only for falsy values like 0, null, or undefined.

Section 2.5: Flattening Arrays

To flatten a multi-dimensional array into a single dimension:

let doubleD = [1, [2, 3, 4, 5], [6, 7], 8, 9];

console.log([].concat(...doubleD)); // Output: [1, 2, 3, 4, 5, 6, 7, 8, 9]

Utilizing the spread operator (...) achieves this effortlessly.

Section 2.6: Dynamic Object Keys

You can create dynamic property names in objects:

const dynamicKey = 'year';

let Car = {

make: 'Toyota',

[dynamicKey]: 1998

};

console.log(Car); // Output: { make: "Toyota", year: 1998 }

This approach allows for greater flexibility in object creation.

Section 2.7: Alternative Looping Techniques

Instead of traditional for loops, you can utilize more concise syntax for iterating over arrays:

// Traditional method

for (let i = 0; i < data.length; i++) {}

// Alternative method

for (let i in data) {}

for (let i of data) {}

Happy coding!