Code JavaScript Examples
Use strict mode: Always use strict mode to enforce better coding practices and catch errors early on. You can enable strict mode by adding “use strict” at the beginning of your code.
Example:
“use strict”;
function myFunction() {
x = 10; // This will throw an error in strict mode
}
Avoid using global variables: Using global variables can lead to unexpected behavior and make it harder to debug code. Instead, use variables with limited scope.
Example:
function myFunction() {
var x = 10; // Declare variables with var, let or const
console.log(x);
}
Use template literals for string concatenation: Template literals make it easier to concatenate strings and variables.
Example:
const name = “John”;
console.log(`My name is ${name}`);
Use arrow functions: Arrow functions provide a more concise syntax and lexical scoping of the “this” keyword.
Example:
const numbers = [1, 2, 3];
const doubledNumbers = numbers.map(num => num * 2);
console.log(doubledNumbers);
Use destructuring: Destructuring allows you to extract values from arrays and objects more easily.
Example:
const person = {
name: “John”,
age: 30,
country: “USA”
};
const { name, age } = person;
console.log(name, age);
Use const and let instead of var: Using const and let instead of var provides better scoping and can prevent redeclaration.
Example:
const PI = 3.14; // Declare constants with const
let x = 10; // Declare variables with let
Use the spread operator: The spread operator allows you to spread elements of an array or object into another array or object.
Example:
const arr1 = [1, 2, 3];
const arr2 = [4, 5, 6];
const combinedArray = […arr1, …arr2];
console.log(combinedArray);
Use promises: Promises provide a better way to handle asynchronous code and prevent callback hell.
Example:
function fetchData() {
return new Promise((resolve, reject) => {
// Perform async operation
if (data) {
resolve(data);
} else {
reject(“Error fetching data”);
}
});
}
fetchData().then(data => console.log(data)).catch(error => console.log(error));
Use let and const for loops: Using let and const for loop variables prevents unexpected behavior due to variable hoisting.
Example:
for (let i = 0; i < 10; i++) {
console.log(i);
}
for (const element of array) {
console.log(element);
}
Use comments: Comments can help explain code and make it easier to maintain.
Example:
// This is a comment
/* This is a
multiline comment */
Summary of points:
- Use strict mode
- Avoid using global variables
- Use template literals for string concatenation
- Use arrow functions
- Use destructuring
- Use const and let instead of var
- Use the spread operator
- Use promises
- Use let and const for loops
- Use comments