JavaScript – ES6 Cheat Sheet | Download PDF
JavaScript ES6 Cheat Sheet
JavaScript ES6 Cheat Sheet with example. ECMAScript 6 – ES6 is the standard specification of JavaScript Which Introduced in 2015 (ES2015). Here’s a cheatsheet to show you .
Download PDF
Recommended: Test your JavaScript knowledge – JavaScript quiz!
Arrow Function
const sum = (a,b) => a + b;
console.log(sum(2,6)) // prints 8
Default Parameters
function print(a = 5) {
console.log(a)
}
print() // prints 5
print(22) // prints 22
Let Scope
let a = 3
if (true) {
let a = 5
console.log(a) // prints 5
}
console.log(a) // prints 3
Const
// can be assigned only once
const a = 55
a = 44 // throws an error
Multi-line String
console.log(
`This is a
multi-line string`
)
Template String
const names = "World"
const message = `Hello ${names}`
console.log(message)
// prints "Hello World"
Recommended: Test your programming knowledge – Programming quiz!
Exponent Operator
const byte = 2 ** 8
// expected result = 256
// Same as: Math.pow(2, 8)
Spread Operator
const a = [ 1, 2 ]
const b = [ 3, 4 ]
const c = [ ...a, ...b ]
console.log(c)
// [1, 2, 3, 4]
String Includes()
console.log('scripts'.includes('s'))
// prints true
console.log('scripts'.includes('m'))
// prints false
// The includes() method is case sensitive. For example, the following expression returns false:
console.log('scripts'.includes('S'))
// prints false
String startsWith()
console.log('scripts'.startsWith('sc'))
// prints true
console.log('scripts'.startsWith('rip'))
// prints false
String repeat()
console.log('st'.repeat(3))
// prints "ststst"
Destructuring array
let [a,b] = [3,7];
console.log(a); // 3
console.log(b); // 7
Destructuring object
let obj = {
a: 77,
b: 66
};
let { a,b } = obj;
console.log(a); // 77
console.log(b); // 66
Object Property Assignment
const a = 2
const b = 5
const obj = { a, b }
// Before es6:
// obj = { a: a, b:b }
console.log(obj)
// prints { a:2, b:5 }
Object.assign()
const obj1 = { a: 1 }
const obj2 = { b: 2 }
const obj3 = Object.assign({},
obj1, obj2)
console.log(obj3)
// { a: 1, b: 2 }
Promises with finally
Promise
.then((result) => { ... })
.catch((error) => { ... })
.finally(() => { /* logic independent of success/error */ })
/* The handler is called when the promise is fulfilled or rejected. */
Spread Operator
const a = {
firstName: "FirstName",
lastName: "LastName1",
}
const b = {
...a,
lastName: "LastName2",
canSing: true,
}
console.log(a)
//{firstName: "FirstName", lastName: "LastName1"}
console.log(b)
/* {firstName: "FirstName", lastName: "LastName2",
canSign: true} */
/* great for modifying objects without side effects/affecting the original */
Destructuring Nested objects
const Person = {
name: "Rezaul karim",
age: 23,
sex: "male",
maritalstatus: "single",
address: {
country: "BD",
state: "Dhaka",
city: "N.Ganj",
pincode: "123456",
},
};
const { address: { state, pincode }, name } = Person;
console.log(name, state, pincode)
// Rezaul Karim Dhaka 123456
console.log(city) // ReferenceError
Object function assignment
const obj = {
a: 5,
b() {
console.log('b')
}
}
obj.b() // prints "b"
Object.entries()
const obj = {
firstName: "FirstName",
lastName: "LastName1",
age: 23,
country: "Bangladesh",
};
const entries = Object.entries(obj);
console.log(entries)
/* prints [
['firstName', 'FirstName'],
['lastName', 'LastName'],
['age', 23],
['country', 'Bangladesh']
];
*/
Conculation
Here’s the ECMAScript 6 cheat sheet list. Hope its helps you to grow up your skills.
Find it helpful? Please share with your friends and Read my others article about coding and programming, Tips, Productivity , Resources etc…
