Let's talk about how to use Node.js to read table data

As web application development becomes more and more important, Node.js has become one of the most commonly used tools among developers. It helps us quickly develop server-side applications, command line tools, and desktop applications. However, sometimes we need to read data from Excel tables or CSV files and use it in our applications. In this article, we will introduce how to use Node.js to read the data of the table.

1. Use Node.js to read data from CSV files

CSV files are comma-delimited text files that are usually used to store tabular data. To read data from CSV files, we need to use the third-party module provided in Node.js - csv-parse.

First, we need to install the csv-parse module. You can use the following command:

npm install csv-parse --save

After the installation is complete, we need to introduce the module in Node.js and then call the parse() function. Parse data from CSV files. Here is an example:

const csv = require('csv-parse');
const fs = require('fs');

fs.readFile('data.csv', (err, data) => {
    csv(data, {
        delimiter: ','
    }, (err, output) => {
        // output是解析后得到的数据
        console.log(output);
    });
});

In the above example, we introduced the csv-parse and fs modules. Then, we use the fs.readFile() function to read the data in the data.csv file and pass it to the csv() function for parsing. After the parsing is completed, we print the output results in the callback function.

2. Use Node.js to read Excel table data

Unlike CSV files, Excel tables are a binary file format. In order to read data from Excel tables, we need to use the third-party module provided in Node.js - xlsx.

To install the xlsx module, you can use the following command:

npm install xlsx --save

After the installation is complete, we need to introduce the module in Node.js. Then, use the readFile() function to read data from the Excel file. The following is an example of reading Excel table data:

const XLSX = require('xlsx');
const workbook = XLSX.readFile('data.xlsx');
const sheet_name_list = workbook.SheetNames;
const xlData = XLSX.utils.sheet_to_json(workbook.Sheets[sheet_name_list[0]]);

console.log(xlData);

In the above example, we introduced the xlsx module and then used the readFile() function to read data from the data.xlsx file. Next, we convert the table data to JSON format through the utils.sheet_to_json() function and store it in the xlData variable. Finally, we print out the xlData variable in the console.

3. Summary

The above is the method of using Node.js to read Excel tables and CSV files. Node.js provides developers with powerful tools, including when reading tabular data. Whether it is a CSV file or an Excel table, we can use some modules provided in Node.js to read the data in it and use it in our application.

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