Performance optimization on type conversion in javascript
Updated: December 14, 2010 21:47:33 Author:
Type conversion is a common mistake for everyone, because JavaScript is a dynamic typed language and you cannot specify the type of a variable.
1. Convert numbers into strings and apply "" + 1. Although it looks a bit ugly, in fact, this is the most efficient. In terms of performance: ("" + ) > String() > .toString() > new String(). Try to use internal operations that can be used during compilation and are faster than those used during runtime. String() is an internal function, so it is very fast, while .toString() needs to query the functions in the prototype, so it is less fast. New String() is used to return an exact copy.
2. Convert floating-point numbers to integers, which is more prone to errors. Many people like to use parseInt(). In fact, parseInt() is used to convert strings into numbers, rather than conversion between floating-point numbers and integers. We should use () or (). In addition, unlike the problem in object search in Section 2, Math is an internal object, so () actually does not have much query method and call time, and the speed is the fastest.
3. For custom objects, if the toString() method is defined for type conversion, it is recommended to explicitly call toString(), because the internal operations will try to try whether the object's toString() method can be converted after trying all possibilities.
2. Convert floating-point numbers to integers, which is more prone to errors. Many people like to use parseInt(). In fact, parseInt() is used to convert strings into numbers, rather than conversion between floating-point numbers and integers. We should use () or (). In addition, unlike the problem in object search in Section 2, Math is an internal object, so () actually does not have much query method and call time, and the speed is the fastest.
3. For custom objects, if the toString() method is defined for type conversion, it is recommended to explicitly call toString(), because the internal operations will try to try whether the object's toString() method can be converted after trying all possibilities.
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