我想使用 nodejs 逐行读取文件,然后在完成后将返回的结果作为 json 字符串获取。我试图这样做,但最后 console.log 打印未定义而不是列表。我得到了列表和 promise 的结尾,但如何将它返回到 main.js 中的调用函数?
我有我的 main.js 文件:
var fct = require('./romlist-parser');
console.log(fct.myfunction());
并且 romlist-parser.js 具有以下内容:
var fs = require('fs');
var readline = require('readline');
exports.myfunction = function() {
var promise = new Promise(function(resolve,reject) {
var rd = readline.createInterface({
input: fs.createReadStream('Atari 2600.txt'),
console: false
});
var games = [];
rd.on('line', function(line) {
var arr = line.split(";");
games.push({name:arr[0], title:arr[1]});
});
rd.on('close', function() {
var json = JSON.stringify(games);
resolve(games);
});
});
promise.then((resolveResult) => {
console.log(resolveResult);
return resolveResult;
});
};
最佳答案
试试这个:
exports.myfunction = function() {
var promise = new Promise(function(resolve,reject) {
var games = [];
var rl = readline('./Atari 2600.txt'); // provide correct file path
rl.on('line', function (line, lineCount, byteCount) {
// console.log(lineCount, line, byteCount);
var arr = line.split(";");
games.push({name:arr[0], title:arr[1]});
})
.on('close', function() {
var json = JSON.stringify(games);
resolve(games); // resolve(json); may be??
})
.on('error', function (e) {
console.log("error", e);
// something went wrong
});
});
promise.then((resolveResult) => {
console.log(resolveResult);
return resolveResult;
});
};
附言此代码可以进一步改进,但为了简单起见,您的理解答案仅限于帖子中发布的样式/代码。否则它可以根据样式改变样式。
关于node.js - nodejs逐行读取文件并在末尾获取其内容,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49783188/