JavaScript was invented by Brendan Eich in 1995, and became an ECMA standard in 1997.
ECMAScript is the official name of the language.
ECMAScript versions have been abbreviated to ES1, ES2, ES3, ES5, and ES6.
Since 2016 new versions are named by year (ECMAScript 2016 / 2017 / 2018).
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
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
var x = 50;
// Here x is 50
{
const x = 16;
console.log(x);// Here x is 16
}
console.log(x); // Here x is 50
Multiline String
console.log(`This is a
multiline string`);
Template string
const name ='Chhetri'
const message =`Buddhadeb ${name}`
console.log(message)
//Prints Buddhadeb Chhetri
Exponent Operator
const byte =2 ** 8
console.log(byte)
//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('apple'.includes('p'))
//Prints true
console.log('apple'.includes('tt'))
//prints false
String StartsWith()
console.log('ab'.repeat(3))
//prints 'ababab'
Destructuring array
let [a,b] =[3,7];
console.log(a);//3
console.log(b);//7
Destucturing object
let obj ={
a:55,
b:44
};
let{a,b}= obj;
console.log(a);
//55
console.log(b);
//44
Object property assignment
const a=2
const b=5
const obj={a,b}
//before es6:
//obj ={a:a,b:b}
console.log(obj)
//{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 handeler is called when the promise is fulfilled or rejected.*/
Top comments (10)
For the Template String example, the line with the template string needs to be wrapped in back ticks instead of single/double quotes or it won’t parse.
The
Object.Assign
example has a similar issue.object
needs to beObject
or else it'll throw a reference error. Same with thepromise
example. 🤦♂️ ...In fact, there are a lot of examples here missing closing quotes or with improper casing which will throw errors.Thanks for the correction I will fixed that.😊
I think the multi-line string example needs back ticks too, and the example code string is showing for me as one line.
Thanks for editing those other examples.
Thanks for the correction:)
Unless you want it to output
'Hello ${name}'
😉Nice post!
There's a typo in
spread operator
first lineThanks bro .
Nice post
Nce
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