object-literal

I have the following object literal: var a = {a:1,b:2} now I want another instance of the same object. If I'm using a constructor, I can do this using the 'new' operator, ie: b = new a(); How to create a new instance of an object using object literals? The simplest way would be with Object.create var b = Object.create(a); console.log(b.a); //1 console.log(b.b); //2 DEMO And of course if you need to support older browsers, you can get the MDN shim for Object.create here 来源： https://stackoverflow.com/questions/9205136/creating-new-objects-using-object-literals

I have this array, in which each index contains an object literal. All of the object literals have the same properties. Some of the object literals have the same value for a given property, and I want to create a new array containing only those object literals. My idea is to sort the array, and slice it into a new array... Here is the array: var arr = []; arr[0] = { country: "United States", num: 27 }; arr[1] = { country: "Australia", num: 5 }; arr[2] = { country: "United States", num: 7 }; So, I want to create a new array containing only those objects where the property country is "United

In the following code, can the x member be accessed from the nested object literal? var outer = { x : 0, inner: { a : x + 1, // 'x' is undefined. b : outer.x + 1, // 'outer' is undefined. c : this.x + 1 // This doesn't produce an error, } // but outer.inner.c is NaN. } In the way you put it - no. You need two stages construction, this will work: var outer = { x : 0 }; // outer is constructed at this point. outer.inner = { b : outer.x + 1 // 'outer' is defined here. }; Not in the construct you have there, no. The main reason being that outer doesn't actually exist yet when you are inside inner

If I have this JS object literal: var foo = { Sussy: 4, Billy: 5, Jimmy: 2, Sally: 1 }; How can I create a new, sorted object literal: var bar = { Sally: 1, Jimmy: 2, Sussy: 4, Billy: 5 }; Re: How to sort a JS Object? Answer: You can't. So instead, you need a more sophisticated data structure. You have many options: You can use a separate array to hold the order of the object's keys. (This is what @Felix Kling's answer demonstrates.) Good: fast retrieval via order or name. Bad: needs a second data structure that must be kept synched with the first. Instead of the Object simply holding

Is there any way to determine in Javascript if an object was created using object-literal notation or using a constructor method? It seems to me that you just access it's parent object, but if the object you are passing in doesn't have a reference to it's parent, I don't think you can tell this, can you? I just came across this question and thread during a sweet hackfest that involved a grail quest for evaluating whether an object was created with {} or new Object() (i still havent figured that out.) Anyway, I was suprised to find the similarity between the isObjectLiteral() function posted

The typical way of creating a Javascript object is the following: var map = new Object(); map[myKey1] = myObj1; map[myKey2] = myObj2; I need to create such a map where both keys and values are Strings. I have a large but static set of pairs to add to the map. Is there any way to perform something like this in Javascript: var map = { { "aaa", "rrr" }, { "bbb", "ppp" } ... }; or do I have to perform something like this for each entry: map["aaa"]="rrr"; map["bbb"]="ppp"; ... Basically, remaining Javascript code will loop over this map and extract values according to criterias known 'at runtime'.