object-literal

I am working on this animation function but I have a problem. I can't seem to perform what should be an easy task, I can not get the length of an object. If you check out that jsFiddle you can see that I am running alert(properties.length); and it is returning undefined . Can anyone see why this might be? JavaScript object simply do not have a length property, only Arrays do. If you want to know the number of properties that are defined on a object, you have to iterate over them and count them. Also, your for in loop is prone to bugs due extension of Object.prototype since in will traverse the

I've read that rather than simply writing a bunch of functions, I should use object literal. Can someone explain what the advantages of object literal are with examples, because I don't understand thus far. Thanks As Russ Cam said, you avoid polluting the global namespace, which is very important in these days of combining scripts from multiple locations (TinyMCE, etc.). As Alex Sexton said, it makes for good code organisation as well. If you're using this technique, I'd suggest using the module pattern. This still uses object literals, but as the return value from a scoping function: var

I need to create an array of object literals like this: var myColumnDefs = [ {key:"label", sortable:true, resizeable:true}, {key:"notes", sortable:true,resizeable:true},...... In a loop like this: for (var i = 0; i < oFullResponse.results.length; i++) { console.log(oFullResponse.results[i].label); } The value of key should be results[i].label in each element of the array. var arr = []; var len = oFullResponse.results.length; for (var i = 0; i < len; i++) { arr.push({ key: oFullResponse.results[i].label, sortable: true, resizeable: true }); } RaYell's answer is good - it answers your question.

This question already has an answer here: Self-references in object literals / initializers 23 answers say I have myfunc({ var1: 1, var2: 2, }) if i want to have a value that makes use of the current unnamed object, how would I do this? eg if I wanted myfunc({ var1: 1, var2: 2, var3: this.var1 + this.var2 }) obviously this does not work. What would the correct syntax be? Unfortunately, that isn't possible. While an object literal is being constructed, no external reference to that object exists until the entire literal is evaluated. The only way to use this at this stage is to use a

I have a json object full of ips like var ips = {} I then add ip objects to this object like so ips[ipID] = {} I then need to add dynamic/variable name value pairs to each ip so I am using code like this var name; var value; var temp = {}; tmp[name] = value My question is, how can I add these name value pairs/ tmp to my ipID objects so that my outcome turns out like ipID = { name : value, anotherName : anotherValue } That's not JSON. It's just Javascript objects, and has nothing at all to do with JSON. You can use brackets to set the properties dynamically. Example: var obj = {}; obj['name'] =

This question already has an answer here: Are 'Arrow Functions' and 'Functions' equivalent / exchangeable? 1 answer Methods in ES6 objects: using arrow functions 4 answers I'm trying to figure out why an arrow function in an object literal is called with window as this . Can someone give me some insight? var arrowObject = { name: 'arrowObject', printName: () => { console.log(this); } }; // Prints: Window {external: Object, chrome: Object ...} arrowObject.printName(); And an object that works as expected: var functionObject = { name: 'functionObject', printName: function() { console.log(this);