Native deep cloning
It's called "structured cloning", works experimentally in Node 11 and later, and hopefully will land in browsers. See this answer for more details.
Fast cloning with data loss - JSON.parse/stringify
If you do not use Date
s, functions, undefined
, Infinity
, RegExps, Maps, Sets, Blobs, FileLists, ImageDatas, sparse Arrays, Typed Arrays or other complex types within your object, a very simple one liner to deep clone an object is:
JSON.parse(JSON.stringify(object))
const a = {
string: 'string',
number: 123,
bool: false,
nul: null,
date: new Date(), // stringified
undef: undefined, // lost
inf: Infinity, // forced to 'null'
re: /.*/, // lost
}
console.log(a);
console.log(typeof a.date); // Date object
const clone = JSON.parse(JSON.stringify(a));
console.log(clone);
console.log(typeof clone.date); // result of .toISOString()
See Corban's answer for benchmarks.
Reliable cloning using a library
Since cloning objects is not trivial (complex types, circular references, function etc.), most major libraries provide function to clone objects. Don't reinvent the wheel - if you're already using a library, check if it has an object cloning function. For example,
- lodash -
cloneDeep
; can be imported separately via the lodash.clonedeep module and is probably your best choice if you're not already using a library that provides a deep cloning function
- AngularJS -
angular.copy
- jQuery -
jQuery.extend(true, { }, oldObject)
; .clone()
only clones DOM elements
- just library -
just-clone
; Part of a library of zero-dependency npm modules that do just do one thing.
Guilt-free utilities for every occasion.
ES6 (shallow copy)
For completeness, note that ES6 offers two shallow copy mechanisms: Object.assign()
and the spread syntax.
which copies values of all enumerable own properties from one object to another. For example:
var A1 = {a: "2"};
var A2 = Object.assign({}, A1);
var A3 = {...A1}; // Spread Syntax
The same as other answers, in a jQuery fashion:
$.each(selectValues, function(key, value) {
$('#mySelect')
.append($("<option></option>")
.attr("value", key)
.text(value));
});
Best Answer
The window.navigator.platform property is not spoofed when the userAgent string is changed. I tested on my Mac if I change the userAgent to iPhone or Chrome Windows, navigator.platform remains MacIntel.
The property is also read-only
I could came up with the following table
Modern macs returns
navigator.platform == "MacIntel"
but to give some "future proof" don't use exact matching, hopefully they will change to something likeMacARM
orMacQuantum
in future.To include iOS that also use the "left side"
Since most O.S. use the close button on the right, you can just move the close button to the left when the user is on a MacLike O.S., otherwise isn't a problem if you put it on the most common side, the right.
http://www.nczonline.net/blog/2007/12/17/don-t-forget-navigator-platform/