如何将JavaScript对象/数组发送到前端-node.js应用程序
我正在尝试将数据发送到我的应用程序前端以创建一个图表。我将数组附加到响应对象中,但这不起作用,尽管我可以使用前端响应对象中发送的用户值如何将JavaScript对象/数组发送到前端-node.js应用程序,javascript,html,mysql,node.js,response,Javascript,Html,Mysql,Node.js,Response,我正在尝试将数据发送到我的应用程序前端以创建一个图表。我将数组附加到响应对象中,但这不起作用,尽管我可以使用前端响应对象中发送的用户值 var scoreQuery = "SELECT q1, q2, q3, q4, q5, q6, q7, q8, q1, q2, q3, q4 FROM table WHERE id = user.id"; var scoreArray; module.exports = function(app, passport){ app.get('/pro
var scoreQuery = "SELECT q1, q2, q3, q4, q5, q6, q7, q8, q1, q2, q3, q4 FROM table WHERE id = user.id";
var scoreArray;
module.exports = function(app, passport){
app.get('/profile', isLoggedIn, function (req, res) {
connection.query(scoreQuery, function (err, result, fields) {
if (err) throw err;
getData(result);
console.log(scoreArray);
}, res.render('profile.ejs', {
user:req.user,
data: scoreArray
})
);
});
};
function getData(result){
Object.keys(result).forEach(function(key) {
const values = result[key];
scoreArray = Object.values(values);
});
});
下面是创建图形的public/javascripts/scripts.js文件
/*Scripts*/
var quizCategory1 = data.scoreArray.slice(0,7);
var quizCategory2 = data.scoreArray.slice(8,11);
var cat1Total = totalScore(category1);
var cat2Total = totalScore(category2);
function totalScore(categoryScore){
return categoryScore = scoreArray.reduce((accum,scoreArray) =>
{
const splitValues = scoreArray.split('/');
return {
score:accum.score + parseInt(splitValues[0]),
maxScore:accum.maxScore + parseInt(splitValues[1]),
}
},{score:0,maxScore:0}
);
}
var ctx = document.getElementById("myChart").getContext('2d');
var barTotalCategoryScores = [cat1Total.score, cat2Total.score];
var labels = ["Java & Design", "Build & Versioning"];
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: labels,
datasets: barTotalCategoryScores
}
}
});
每当用户登录时,scoreArray就会打印到控制台,这样sql查询和getData()函数就可以工作了。但是当我尝试在scripts.js文件中使用data.scoreArray时,它不起作用。添加新路由:
app.get('/profile/:id', (req,res) => {
// your_array = query DB with param id (req.params.id) store in your array
res.status(200).json({data: <your_array>})
})
app.get('/profile/:id',(req,res)=>{
//your_array=使用数组中的param id(req.params.id)存储查询数据库
res.status(200).json({data:})
})
然后在客户机上对/profile/:id()进行GET查询
页面加载时(window.onload)
对于MySQL,您应该使用:
// ... your routes
// + new route
app.get('/profile/:id', (req,res) => {
let id = req.params.id // e.g /profile/3 -> req.params.id = 3
let scoreArray;
// your query (it's very bad to set param in your query like this (injection SQL) )
let scoreQuery = `SELECT q1, q2, q3, q4, q5, q6, q7, q8, q1, q2, q3, q4 FROM
table WHERE id = ${id}`; // `... ${foo}` => https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Litt%C3%A9raux_gabarits
connection.query(scoreQuery, function (err, result, fields) {
if (err) throw err;
getData(result);
console.log(scoreArray);
}, res.status(200).json({
user:req.user,
data: scoreArray
})
);
})
// ... your method
function getData(result){
Object.keys(result).forEach(function(key) {
const values = result[key];
scoreArray = Object.values(values);
});
});
客户:
/* code to get data
let id_test = 1;
fetch(`http://localhost:<your_node_server_port>/profil/${id_test}`)
.then(response => response.json())
.then(json => console.log(json)) // return profil for id 1
*/
// e.g page is loaded
window.onload = () => {
let id_test = 1;
fetch(`http://localhost:<your_node_server_port>/profil/${id_test}`)
.then(response => response.json())
.then(json => console.log(json)) // return profil for id 1
}
/*获取数据的代码
设id_检验=1;
取回(`http://localhost:/profil/${id\u test}`)
.then(response=>response.json())
.then(json=>console.log(json))//返回id为1的profile
*/
//例如,页面已加载
window.onload=()=>{
设id_检验=1;
取回(`http://localhost:/profil/${id\u test}`)
.then(response=>response.json())
.then(json=>console.log(json))//返回id为1的profile
}
非常感谢Sylvain,你的解释让我走上了正确的道路。我做了以下的
//routes.js
app.get('/profile', function (req, res) {
let id = req.user.id;
getData(id, function (score) {
res.status(200).render('profile.ejs',{user: req.user, score})
});
});
我将sql语句放入getData()
函数中,并在sql语句中使用“?”
代替id,并将id参数作为值发送到查询方法中。这已经奏效了,我现在可以使用
在客户端ejs文件上获取score对象
我现在的问题仍然是试图在我的public/javascripts/scripts.js文件中使用score.cat1Total.score
,但它没有定义。。。我不知道如何正确地实现window.onload()
方法
// /public/javascripts/scripts.js
/* code to get data?
window.onload = () => {
fetch(`http://localhost:8080/profile)
.then(response => response.json())
.then(json => console.log(json))
}
*/
var ctx = document.getElementById("myChart").getContext('2d');
//This is where I am trying to get score objects values.
var barTotalCategoryScores = [score.cat1Total.score, cat2Total.score];
var labels = ["Java & Design", "Build & Versioning"];
var myChart = new Chart(ctx, {
type: 'bar',
data: {
labels: labels,
datasets: barTotalCategoryScores
}
}
});
下面是我在routes中使用的getData(id,callback)
方法供参考
// routes.js
function getData(id, callback) {
let scoreQuery = "SELECT c1q1, c1q2, c1q3, c1q4, c1q5, c1q6, c1q7, c1q8, c2q1, c2q2, c2q3, c2q4 FROM nodejs_login.assessment_score AS a JOIN nodejs_login.users as u ON a.respondent_id = u.user_respondent_id WHERE a.respondent_id = ?";
connection.query(scoreQuery, [id],function (err, result) {
if (err) throw err;
Object.keys(result).forEach(function(key) {
let values = result[key];
let scoreArray = Object.values(values);
let category1 = scoreArray.slice(0,7);
let category2 = scoreArray.slice(8,11);
//parsing and accumlating each category score
var cat1Total = totalScore(category1);
var cat2Total = totalScore(category2);
//function to parse the strings into numbers and accumulate them
function totalScore(categoryScore){
return categoryScore.reduce((accum,scoreArray) =>
{
const splitValues = scoreArray.split('/');
return {
score:accum.score + parseInt(splitValues[0]),
maxScore:accum.maxScore + parseInt(splitValues[1]),
}
},{score:0,maxScore:0}
);
}
let categories = {cat1Total, cat2Total};
callback(categories);
});
})
}
感谢您的帮助:)您将如何以及在何处在客户端实现get查询?我是一个初学者。而且,我实际上不理解这一点//你的数组中存储有参数id(req.params.id)的查询DB是我在顶部的DB查询,var scoreQuery?:id指的是什么?你的数组这是你客户端需要的数据(scoreArray)检查:对不起,我真的不明白这是什么意思“(req.params.id)存储在你的数组中”。req是你的请求对象,包含param/:id(express)