This question already has answers here:
What does the arrow function with a () after means? [duplicate]
(3 answers)
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 4 years ago.
I just came across this code:
routes: routes.map(route => ({
Notice the arrow function being followed by a closure. Why are closures used here?
see this repo for reference: https://github.com/prograhammer/vue-pizza/blob/master/src/http/router.js#L33
It returns an object. The parenthesis is to denote that this is an object not a block.
() => {return {hello: 'world' } } === () => ({hello: 'world'})
Related
This question already has answers here:
What does this symbol mean in JavaScript?
(1 answer)
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 2 years ago.
editable: params => this.isEditable(applied)(params)
this editable get boolean value by calling iseditable function by passing applied as a paramaters. but params is get passed with it. what is the meaning of this code?
Well, you only showed a small snippet, but I suspect it's something along the lines as
{// Some object is being constructed...
editable: params => this.isEditable(applied)(params)
}
Which is an ES6 "arrow function expression", which returns some other function, as the return value of calling isEditable.
//Some object is being constructed...
{
editable: function ( params ){
return this.isEditable(applied)(params)
},
// More properties being defined...
}
You can learn more about ES6 arrow function expressions here https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions
This question already has answers here:
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 5 years ago.
I searched for
"()=>{} in js"
on Google
But it's not displaying relative results
What is it?
=> is a shortcut for an anonymous function. So that's just a function that does nothing. equivalent to:
function () { }
This question already has answers here:
ECMAScript 6 arrow function that returns an object
(6 answers)
Closed 5 years ago.
Is it possible to write the code below in one line (without return keyword)?
elements.map(element => {
return {...element, selected: false};
})
Yes, by using the concise arrow form, enclosing the object initializer in ():
elements.map(element => ({...element, selected: false}));
// ---------------------^-----------------------------^
You need the () because otherwise the { of the object initializer is read as the { as the beginning of a function body. The ( instead makes it an expression body with implied return.
This question already has answers here:
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 5 years ago.
I have recently come across this code with which I am unfamiliar:
const foo = () => {
/*code block here*/
}
As far as I can tell, it means the same thing as:
const foo = function () {
/*code block here*/
}
Is that a correct assumption, or are there differences?
What is the correct name to refer to this bit of code?
What exactly is the '=>' doing? I've never seen it in Javascript before.
This is ES6 arrow function. It's basically same as function (){},
with some differences such as not rebinding this.
Reference on MDN
This question already has answers here:
What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?
(14 answers)
Closed 7 years ago.
I am just learning Spring react, I don't know Javascript very well. I got to code:
componentDidMount: function () {
client({method: 'GET', path: '/api/employees'}).done(response => {
this.setState({employees: response.entity._embedded.employees});
});
There is written:
componentDidMount is the API invoked after React renders a component
in the DOM.
I was looking for what Javascript operator => means. But don't found anything.
This is an arrow function.
An arrow function expression (also known as fat arrow function) has a shorter syntax compared to function expressions and lexically binds the this value (does not bind its own this, arguments, super, or new.target). Arrow functions are always anonymous.
You can see a simple example:
var vec = ['a', 'ab', 'abc'];
var test = vec.map(i => i.length);
alert(test); // 1,2,3