Exploring JavaScript: Prototypes is too powerful

Expanding the prototype attribute of constructor is a very powerful method to add features, but sometimes it is too powerful

Expanding the prototype attribute of constructor is a very powerful method to add features, but sometimes it is too powerful.

Adding built-in constructor prototypes (such as Object (), Array (), or Function () is attractive, but this seriously reduces maintainability, it makes your code unpredictable. Other developers who use your code are more likely to use the built-in JavaScript method for continuous work than the method you add.

In addition, attributes added to the prototype may be displayed in the loop when the hasOwnProperty attribute is not used, which may cause confusion.

Therefore, it is best not to add a built-in prototype. You can specify a rule, except when the current conditions are met:

• It is expected that this function will be implemented as a built-in method in future ECMAScript or JavaScript implementations. For example, you can add the method described in ECMAScript 5 until all browsers catch up. In this case, you just defined the useful methods in advance.
• If you check that your custom property or method does not exist, it may have been implemented elsewhere in the code or it is already part of the browser JavaScript Engine that you support.
• You have clearly documented and communicated with the team about the changes.

If the three conditions are met, you can add the prototype as follows:

If (typeof Object. protoype. myMethod! = "Function") {Object. protoype. myMethod = function () {// implementation ...};}

Additional reading

The topic list of this article is as follows:

1. How should we understand the working principle of the JavaScript engine?
2. JavaScript exploration: the importance of writing maintainable code
3. JavaScript exploration: exercise caution when using global variables
4. JavaScript exploration: var pre-parsing and side effects
5. JavaScript exploration: for Loop (for Loops)
6. JavaScript exploration: for-in loop (for-in Loops)
7. Exploring JavaScript: Prototypes is too powerful
8. JavaScript: eval () is the devil"
9. JavaScript exploration: Using parseInt () for Numerical Conversion
10. Exploring JavaScript: Basic coding specifications
11. JavaScript exploration: function declaration and function expression
12. JavaScript exploration: Name function expressions
13. JavaScript: function name in the debugger
14. JavaScript: JScript Bug
15. JavaScript exploration: Memory Management of JScript
16. Exploring JavaScript: SpiderMonkey's quirks
17. JavaScript exploration: an alternative solution to naming function expressions
18. JavaScript exploration: Object
19. JavaScript exploration: Prototype chain
20. JavaScript exploration: Constructor
21. JavaScript probing: executable context Stack
22. Execution context 1: Variable object and activity object
23. Execution context 2: Scope chain Scope Chains
24. Execution context 3: Closure Closures
25. Execution context 4: This pointer
26. Exploring JavaScript: Powerful prototype and prototype chain
27. JavaScript Functions 1: function declaration
28. JavaScript function 2: function expressions
29. JavaScript function 3: function expressions in a group
30. JavaScript function 4: function Constructor
31. JavaScript variable object 1: VO Declaration
32. JavaScript variable object 2: VO in different execution contexts
33. JavaScript variable object 3: two stages of execution Context
34. JavaScript variable object IV: Variables
35. Property of the JavaScript variable object __parent _
36. JavaScript scope chain 1: Scope chain Definition
37. JavaScript scope chain 2: function Lifecycle
38. JavaScript scope chain 3: Scope chain features
39. JavaScript closure 1: Introduction to closures
40. JavaScript closure 2: Implementation of closure
41. JavaScript closure 3: Closure usage

This article is available at http://www.nowamagic.net/librarys/veda/detail/1626.