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Javascript Closures

Javascript Closures
Introduction Closure A "closure" is an expression (typically a function) that can have free variables together with an environment that binds those variables (that "closes" the expression). Closures are one of the most powerful features of ECMAScript (javascript) but they cannot be property exploited without understanding them. They are, however, relatively easy to create, even accidentally, and their creation has potentially harmful consequences, particularly in some relatively common web browser environments. To avoid accidentally encountering the drawbacks and to take advantage of the benefits they offer it is necessary to understand their mechanism. This depends heavily on the role of scope chains in identifier resolution and so on the resolution of property names on objects. The simple explanation of a Closure is that ECMAScript allows inner functions; function definitions and function expressions that are inside the function bodes of other functions. Assignment of Values Finally:- An

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Truth, Equality and JavaScript You don’t have to be a JavaScript novice to get confused by this… or this… The good news is that there is a standard and all browsers follow it. Some authors will tell you to fear coercion and and code against it. I hope to persuade you that coercion is a feature to be leveraged (or at the very least understood), not avoided… Is x true? Does x equal y?

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Learning JavaScript Design Patterns Design patterns are reusable solutions to commonly occurring problems in software design. They are both exciting and a fascinating topic to explore in any programming language. One reason for this is that they help us build upon the combined experience of many developers that came before us and ensure we structure our code in an optimized way, meeting the needs of problems we're attempting to solve. Design patterns also provide us a common vocabulary to describe solutions. This can be significantly simpler than describing syntax and semantics when we're attempting to convey a way of structuring a solution in code form to others. In this book we will explore applying both classical and modern design patterns to the JavaScript programming language.

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