使用 Express.js 的 BMI 计算器

体重指数（BMI）以个体的体重和身高表示。它是体重与身高平方的比值，分别以公斤和米为单位。

BMI = (weight of body) / (height of body)2
Unit of weight: Kilogram(Kg);
Unit of height: Meter(m);
Unit of BMI is kg/m2

方法：

• 首先，我们编写HTML 代码来创建一个表单，我们将从用户那里获取姓名、身高（m）、体重（kg）作为输入。
• 导入 require 模块并将其存储到 app 变量中
• 使用此发送 html 并在特定路由上发布数据
  

app.post("/bmicalculator", function (req, res) {
    heigh = parseFloat(req.body.Height);
    weigh = parseFloat(req.body.Weight);
    bmi = weigh / (heigh * heigh);

• 使用公式检查 BMI 的条件。
  

第1步：

HTML

    
        
        
        
        
    
    
        

            
BMI-CALCULATOR
        
 
        

            
            

            
            

            
            

            Get-BMI
        
    

输出：

简单的形式

现在让我们为我们的计算和功能编写代码，这是我们 BMI-CALCULATOR 的主要部分。

第2步

Dependencies: 
express:    npm install express
bodyparser:   npm install body-parser

Javascript

//importing modules
const express = require("express");
const bodyparser = require("body-parser");
 
// stores the express module into the app variable!
const app = express();
app.use(bodyparser.urlencoded({ extended: true }));
 
//sends index.html
app.get("/bmicalculator", function (req, res) {
    res.sendFile(__dirname + "/" + "index.html");
});
 
//this is used to post the data on the specific route
app.post("/bmicalculator", function (req, res) {
    heigh = parseFloat(req.body.Height);
    weigh = parseFloat(req.body.Weight);
    bmi = weigh / (heigh * heigh);
 
    //number to string format
    bmi = bmi.toFixed();
 
    req_name = req.body.Name;
 
    // CONDITION FOR BMI
    if (bmi < 19) {
        res.send("
hey! " + req_name +
                 " your BMI is around: " + bmi +
                 "
You are Underweight!");
    } else if (19 <= bmi && bmi < 25) {
        res.send("
hey! " + req_name +
                 " your BMI is around: " + bmi +
                 "
You are Normalweight!");
    } else if (25 <= bmi && bmi < 30) {
        res.send("
hey! " + req_name +
                 " your BMI is around: " + bmi +
                 "
You are Overweight!");
    } else {
        res.send("
hey! " + req_name +
                 " your BMI is around: " + bmi +
                 "
You are Obese!");
    }
});
 
//this is used to listen a specific port!
app.listen(7777, function () {
    console.log("port active at 7777");
});

输出：

最终输出：

输出