Javascript-practice

Javascript code snippets

var, let, const

• var -> function scoped. variable declared with var is visible everywhere inside the function its declared in.
• let -> block scoped. variable declared with let is visible everywhere inside the block its declared in. A let variable can only be declared once, defined multiple times.
• const -> block scoped. variable declared with const is visible everywhere inside the block its declared in. A const variable can only be declared once. Value has to be assigned at the time of declaration.

some code snippets

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Arrow function

Syntax for regular JS functions: const square = function(num) { return num * num; }

Syntax for arrow functions:

const square = (num) => { return num * num; }

or

const square = num => num * num; //note that we can remove the parentheses in the parameters in case of only 1 parameter being passed.

In case of no parameter,

const dummy = () => console.log("dummy function");

Note: Arrow functions don't rebind the 'this' keyword.

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Template literals

template literals.js

Note: Template literals allow us to have multi-line strings. For example, see this.

Object destructuring

object destructuring.js

Spread operator

ES6 spread operator helps us construct new arrays/objects by 'spreading' the existing arrays/objects.

Spreading arrays, spreading objects

spread operator example.js

ES6 Classes

Modules

Named and Default exports

named and default exports.js

padStart() and padEnd()

The padStart function is used for padding the start of a string. The padEnd function is used for padding the end of a string.

padStart and padEnd.js

Notes

• In JS, functions are objects.
• Using JS 'bind' method, one can bind a method to a JS object to avoid ambiguous behavior of JS 'this' keyword.

Resources

Mosh ES6 Tutorial