ecmascript-5 | 易学教程

Is there anyway to have instances share the same function yet at the same time have private variables?

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问题 I have this piece of code: var Human=function(name){ this._name=name; }; Human.prototype.Shout=function(){ alert(this._name); }; var tom=new Human("tom"); var john=new Human("john"); alert(tom.Shout===john.Shout); Right now ._name is not "private". I want to make ._name "private", but at the same time i do not wish to create additional functions for each instance of Human (in other words tom.Shout Must be === to john.Shout) because creating additional functions for each instance is just well.

How does inheritance work in ES5-Javascript?

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For the below code, var customer={ name: "Tom Smith", speak: function(){ return "My name is " + this['name']; }, address: { street: '123 Main St', city: "Pittsburgh", state: "PA" } }; Below is my visualisation of customer object, My question: Does customer object inherit properties(built-ins) of Object.prototype only? Are the properties(built-ins) of Object function type object are also for the purpose of inheritance? If yes, What is the syntax for customer object to inherit Object properties? Bergi Below is my visualisation of customer object It would be better if you used the term [

How do JavaScript versions correlate to ECMAScript versions?

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问题 For example, [].map was "implemented in JavaScript 1.6." Is that an ES5 method? How does the 1.6 correlate to an ECMAScript version? 回答1: There aren't really strict correspondences between the version numbers Mozilla uses and the ECMAScript standard's version numbers. There's a table on Wikipedia that might be what you're looking for -- you'll see that JavaScript 1.6 corresponds to ECMAScript 3 and then some additional extensions. [].map specifically was standardized in ECMAScript 5, but to

Is there a library which implements new Javascript/Ecmascript 5 methods for older versions?

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问题 Although Ecmascript 5 introduces some completely new features, it also adds some new methods (bind, trim, map, etc.) which should be perfectly possible to implement (albeit slower) in current versions. Does a library exist which implements these backwards compatible features (and no more, excluding Prototype et. al.) 回答1: Kris Kowal and friends have built the es5-shim. It was part of Narwhal, but now lives on its own: http://github.com/kriskowal/es5-shim/ Was: I've taken to using the global

OLOO how to access private variable

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In the following example I am using Kyle Simpson's "OLOO (Objects Linking to Other Objects) Pattern" to create a simple example of object serialization. I need to keep variable _data private (I am using a closure) and expose its properties only with getter and setters which are create on object instance level (in init ). Currently I defined function toJson inside init so it can access _data and it works but, I would like to know: If would be possible to move toJson function outside init (place it at same level of fromJson ) so it will accessible via protoype chain but allowing to access _data

How can I tell when this.setState exists in ES6?

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I have been struggling with trying to migrate my React code from ES5 to ES6. As I have found out by now, this is no longer automatically bound which causes all sorts of hell. I am trying to figure out by trial and error what objects are being passed around. So far I can find everything and adjust accordingly. However when it comes to this.setState I am having problems because it is not visible in console.log !!!! See screenshot in ES5: and here is the same kind of code in ES6: Please teach me how to fish i.e. help me figure out how to understand when an object has this.setState or not? things

Jint Array functions ECMA 5.1

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I'm attempting to use Jint (v2.10.4.0) to translate one arbitrary JSON structure to another. However, I am having issues with using map . According to the ECMA 5.1 language spec, map should exist on Array.prototye. However, when I attempt to use it, I get an error: Jint.Runtime.JavaScriptException: 'Object has no method 'map'' I'm testing this like Engine engine = new Engine(); var doubles = engine.SetValue("x", "[ 1, 2, 3, 4, 5 ]") .Execute("x.map(function(a){ return a + a; })") .GetCompletionValue() .ToObject(); Console.WriteLine(doubles); Console.ReadKey(); Ideally, I'd also like to use

Why the property “prototype” is absent in definition methods of ES6 classes

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问题 Es6, Classes there. We have the method (go) like this : the example in ES6 class X{ go(){} } var y = new X(); var z = new y.go(); console.log(z) Example of the Error Screen Shot: We don't have property prototype of this method (go), so we can't create new Object from this method. This is the fact. But I can't understand WHY? Why the developers of javascript in ES6 don't let me use this functionality. Vice versa in ES5 we can create new instance from Object's methods. Of course, it works from

Writing ECMAScript5 compliant code

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I want to build a library in JavaScript/JScript/ECMAScript...whatever you want to call it, which will target modern standards (HTML5, CSS3, ESv5) with that in mind, any browser that supports the standard! Now I know there are already plenty of useful libraries out there, i.e. jQuery and MooTools. Of course they're great and I already use those where necessary, but I should not be forced to jump on the same bandwagon as every other developer just because it's popular! So for the sake of the following questions, let us not concern ourselves with 3rd party libraries such as jQuery and MooTools.

How do I call the Tamarin ESC Compiler from AS3 Code?

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问题 I'm trying to call Tamarin's ESC Compiler from AS3 code. I've got the ESC Compiler byte code loaded in Flash Player, but when I call it, the ESC Compiler always returns the same do nothing byte code, no matter what source code I feed it. The human readable ESC code looks like this: function compileStringToBytes(input, context="(string)", start_line=1) { let [_,_,res] = compile( (function () input), (function (abc) abc.getBytes()), context, start_line ); return res; } I'm calling it using the