JSON数组转换为nodejs可读对象流
JSON数组转换为nodejs可读对象流
提问于 2018-05-30 23:47:09
我有一个事件，每当从蓝牙设备接收到数据包时都会触发。数据包以JSON数组的形式传入，并始终包含10个对象，类似于下面的对象。
var s1_data = [{"record":0,"sensor":1,"timestamp":26566,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":1,"sensor":1,"timestamp":26567,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":2,"sensor":1,"timestamp":26568,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":3,"sensor":1,"timestamp":26569,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":4,"sensor":1,"timestamp":26570,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":5,"sensor":1,"timestamp":26571,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":6,"sensor":1,"timestamp":26572,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":7,"sensor":1,"timestamp":26573,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":8,"sensor":1,"timestamp":26574,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}},
{"record":9,"sensor":1,"timestamp":26575,"date":{"day":7,"hour":10,"minute":45,"month":5,"second":38,"year":18}}]我需要将每个单独的对象推入另一个流正在使用的node.js流中。
有没有人能举个例子，说明我如何不断地将这些推送到一个可读的对象流中(或者我需要使用PassThrough流)吗？我似乎不知道该怎么做！
编辑以添加下面的示例代码。chunk.toString()失败，因为块是未定义的
var Readable = require('stream').Readable;
var util = require('util');
var through2 = require('through2');
var s1 = require('./sensor1.js');
var s2 = require('./sensor2.js');
var minLength = s1.length;
//console.log(s1);
var s1stream = new Readable({ objectMode: true });
var s2stream = new Readable({ objectMode: true });
s1stream._read = function () {
this.push();
};
s2stream._read = function () {
this.push();
};
if (s2.length < minLength){
minLength = s2.length;
}
var n1 = 0;
setInterval(function() {
if (n1++ < minLength) {
console.log(s1[n1].record);
s1stream.push(s1[n1]);
} else if (n1++ === minLength) {
s1stream.push(null);
}
}, 1000);
var n2 = 0;
setInterval(function() {
if (n2++ < minLength) {
s2stream.push(s2[n2]);
} else if (n2++ === minLength) {
s2stream.push(null);
}
}, 1000);
s1stream.pipe(through2.obj(function (chunk, enc, callback) {
this.push(chunk.toString())
callback()
})).pipe(process.stdout);下面的编辑显示了工作代码。看起来这与我创建 read functions的方式有关
var Readable = require('stream').Readable;
var util = require('util');
var through2 = require('through2');
var Transform = require('stream').Transform;
var s1 = require('./sensor1.js');
var s2 = require('./sensor2.js');
var minLength = s1.length;
//console.log(s1);
var s1stream = new Readable({
objectMode: true,
read() {}
})
const s2stream = new Readable({
objectMode: true,
read() {}
})
if (s2.length < minLength){
minLength = s2.length;
}
var n1 = 0;
setInterval(function() {
if (n1 < minLength) {
s1stream.push(s1[n1]);
n1++;
} else if (n1 == minLength) {
s1stream.push(null);
}
}, 1000);
var n2 = 0;
setInterval(function() {
if (n2++ < minLength) {
s2stream.push(s2[n2]);
} else if (n2++ === minLength) {
s2stream.push(null);
}
}, 1000);
var jsonStream = through2.obj(function(file, encoding, cb) {
this.push(file.record.toString())
cb()
})
s1stream.pipe(jsonStream).pipe(process.stdout);回答 1
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/50608850
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