What are the Subtle Differences Between `parseInt()` and `Number()` in JavaScript?

Exploring the Subtle Distinction between parseInt() and Number() in JavaScript

When converting strings to numbers in JavaScript, the similarity between the parseInt() and Number() functions can lead to confusion. However, despite sharing this core purpose, they exhibit semantic differences that warrant further examination.

parseInt(): The Parsing Function

Unlike Number(), which performs type conversion, parseInt() serves primarily as a parsing function. This distinction means that parseInt() attempts to interpret the string as a numeric representation while disregarding any trailing characters that do not align with the specified base (default: decimal).

Number(): The Type Conversion Constructor

By contrast, Number() invokes the Number constructor, which behaves like a function when called without the new keyword. This function performs type conversion, transforming various values (including strings) into numeric equivalents. Unlike parseInt(), Number() does not ignore trailing characters and can interpret exponential notation.

Explicit vs Implicit Octal Interpretation

Interestingly, Number() does not automatically recognize implicit octal notation (e.g., "010"), but it can handle explicit octal表記法，如"0o10."另一方面，parseInt()将隐式八进制表示法解释为八进制数字，除非显式指定十进制基数(e.g., "010",10)。

Hexadecimal Notation Support

Both parseInt() and Number() support hexadecimal notation and interpret strings like "0xF" as integers correctly.

Unary Operator for Numeric Type Conversion

值得注意的是，一元 运算符也可以用来进行数字类型转换，与使用Number()构造函数作为函数的效果相同。然而，它更简洁，不需要显式调用Number()函数。

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