Number conversions using parseInt() and toString() in JavaScript

Anyone who codes in JavaScript regularly has made use of parseInt() to convert an integer that's expressed as a string into an actual number type that one can use in calculations.

The MDN defines the use of parseInt() as follows:

复制代码
parseInt(string)
parseInt(string, radix)

string is the value to parse. In the case that it's not a string type, it is internally converted to a string before the parsing occurs.

radix is a value between 2 and 36 which is the base of the string parameter value. It does NOT default to base 10 if this parameter is omitted. For example, a string with the prefix "0x" will default to base 16, hexadecimal. To learn in greater detail how various inputs are treated, please refer to the MDN article on parseInt() for more details.

parseInt()

parseInt() can be used to convert numbers to and from various bases if one understands how the radix parameter functions.

For example:

复制代码
parseInt("23", 4)
parseInt("0x23")
parseInt("23", 2)

will output:

复制代码
11
35
NaN

In each case we are answering the question: "What is the base 10 value of 23 in base 4? in base 16? in base 2?"

  1. "23" in base 4 is 2 * 4 + 3, or 11 in base 10.
  2. "0x23" implies base 16. 2 * 16 + 3, or 35 in base 10
  3. "23" in base 2 is NaN, since base 2 digits can only include 0 and 1.

Imagine how useful this could be if someone needs you to quickly interpret binary "1110010"!

复制代码
parseInt("1110010", 2)

will give us the correct base 10 number:

复制代码
114

toString(radix)

Using toString(radix) with a number object overrides the the Object object method toString(). When used with number objects, toString(radix) returns a string representation of the number object in the specified base.

toString(radix) answers the question: "How do I write the value 23 in base 4? in base 16? in base 2?"

复制代码
let num = 23

num.toString(4)
num.toString(16)
num.toString(2)

And the output:

复制代码
113
17
10111

In effect, parseInt() and toString() act as inverses of each other:

复制代码
let num = 23

parseInt(num.toString(4), 4)
parseInt(num.toString(16), 16)
parseInt(num.toString(2), 2)

And the result:

复制代码
23
23
23

toString(2) is particularly useful if you need to generate the binary representation of a number for any reason. Or how about converting a hexadecimal number (base 16) into its binary equivalent?

复制代码
parseInt("1F4", 16).toString(2)

"111110100"

(in case you were wondering, this is 500 in base 10!)

I hope this brief exploration of these two related methods leaves you with a greater understanding of how they go beyond converting integers to strings and vice versa. They can be used to translate numbers to and from other bases, as well!

At last ,If you want to protects your javascript code from being illegally analyzed, hacked, and stolen.You can obfuscate js with js-obfuscator or jshaman etc.

Happy Coding!

相关推荐
【ql君】qlexcel23 分钟前
Notepad++ 复制宏、编辑宏的方法
开发语言·javascript·notepad++··宏编辑·宏复制
Zevalin爱灰灰32 分钟前
MATLAB GUI界面设计 第六章——常用库中的其它组件
开发语言·ui·matlab
冰糖猕猴桃39 分钟前
【Python】进阶 - 数据结构与算法
开发语言·数据结构·python·算法·时间复杂度、空间复杂度·树、二叉树·堆、图
就改了1 小时前
Ajax——在OA系统提升性能的局部刷新
前端·javascript·ajax
凌冰_1 小时前
Ajax 入门
前端·javascript·ajax
wt_cs1 小时前
银行回单ocr api集成解析-图像文字识别-文字识别技术
开发语言·python
奋飛1 小时前
TypeScript系列:第六篇 - 编写高质量的TS类型
javascript·typescript·ts·declare·.d.ts
_WndProc1 小时前
【Python】Flask网页
开发语言·python·flask
sunbyte2 小时前
50天50个小项目 (Vue3 + Tailwindcss V4) ✨ | ThemeClock(主题时钟)
前端·javascript·css·vue.js·前端框架·tailwindcss
小飞悟2 小时前
🎯 什么是模块化?CommonJS 和 ES6 Modules 到底有什么区别?小白也能看懂
前端·javascript·设计