What do the curly braces surrounding JavaScript arguments for functions do?
var port = chrome.extension.connect({name: "testing"});
port.postMessage({found: (count != undefined)});
It's an object literal. Show activity on this post. Basically the curly braces {} are the another way for creating objects in javascript. This is equivalent to the "new Object()" syntax.
Yes, it works, but only up to a single line just after an 'if' or 'else' statement. If multiple lines are required to be used then curly braces are necessary.
To edit JavaScript code, you can use the same techniques that you use to edit HTML or CSS. However, a JavaScript file must have the . js extension. By default, when you type the left brace, left parenthesis, or left quotation mark in a JavaScript statement, Brackets adds the right brace, parenthesis, or quotation mark.
No, curly braces are not necessary, However, one very important reason to use the curly brace syntax is that, without it, there are several debuggers that will not stop on the line inside the if statement.
A second possible answer has arisen since this question was asked. Javascript ES6 introduced Destructuring Assignment.
var x = function({ foo }) { console.log(foo) } var y = { bar: "hello", foo: "Good bye" } x(y) Result: "Good bye"
The curly braces denote an object literal. It is a way of sending key/value pairs of data.
So this:
var obj = {name: "testing"};
Is used like this to access the data.
obj.name; // gives you "testing"
You can give the object several comma separated key/value pairs, as long as the keys are unique.
var obj = {name: "testing", another: "some other value", "a-key": "needed quotes because of the hyphen" };
You can also use square brackets to access the properties of the object.
This would be required in the case of the "a-key"
.
obj["a-key"] // gives you "needed quotes because of the hyphen"
Using the square brackets, you can access a value using a property name stored in a variable.
var some_variable = "name"; obj[ some_variable ] // gives you "testing"
Curly braces in javascript are used as shorthand to create objects. For example:
// Create an object with a key "name" initialized to the value "testing"
var test = { name : "testing" };
alert(test.name); // alerts "testing"
Check out Douglas Crockford's JavaScript Survey for more detail.
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