Node.js - How to read data from a file and integrate the output into variable

Question

Im new to Node.js and would like to read the content of a simple html file, which is either "1" or "0". After that I would like to put it into the variable "sensorReading".

I found out that I could read the content with:

fs =require('fs')
fs.readFile('/home/pi/status.html', 'utf8', function (err,data){
if (err) {
return console.log(err);
}
console.log(data);
});

This gives me either "1" or "0" as a console output. But I would like to have the value in another variable. Here's a snippet of the code which I need it for:

garage
.getService(Service.GarageDoorOpener)
.setCharacteristic(Characteristic.CurrentDoorState, Characteristic.CurrentDoorState.CLOSED)
.setCharacteristic(Characteristic.ObstructionDetected, Characteristic.ObstructionDetected.NO)
.getCharacteristic(Characteristic.CurrentDoorState)
.on('get', function(callback) {

var err = null;

wpi.setup('phys');
sensorReading = wpi.digitalRead(12);
sensorReading = Number(sensorReading);
if (sensorReading == '1'){
GARAGE_DOOR.opened = false;
}
if (sensorReading == '0'){
GARAGE_DOOR.opened = true;
}

if (GARAGE_DOOR.opened) {
console.log("Query: Is Garage Open? Yes.");
callback(err, Characteristic.CurrentDoorState.OPEN);
}
else {
console.log("Query: Is Garage Open? No.");
callback(err, Characteristic.CurrentDoorState.CLOSED);
}
});

Normally the value for "sensorReading" comes from a GPIO of the Raspberry Pi but I would like to have the value out of my file.

Please forgive me if I named something wrong, or if it's a stupid question but I couldn't find a solution for my kind of task.

Thanks in advance :)

just use require() to get the file and blah blah to get the part you want and use var e = eval(partyouwantasvar); and whala! (Note: eval best be used safe as if it's used incorrectly, it can break things) — user4616966
– user4616966, Commented Dec 21, 2017 at 23:00
Thanks for the fast answer but I'm sorry, I don't know how I need to put this into my code :/ — Ridgeback09
– Ridgeback09, Commented Dec 21, 2017 at 23:09
@TyQ. - What are you expecting require() to do with a text file? — jfriend00
– jfriend00, Commented Dec 22, 2017 at 0:01

langitbiru · Accepted Answer · 2017-12-21 23:11:51Z

1

have you try sensorReading = fs.readFileSync('/home/pi/status.html', 'utf-8')

answered Dec 21, 2017 at 23:11

langitbiru

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1 Comment

Ridgeback09 Over a year ago

This looks like it would work best for me :) Do I have to put fs = require('fs') at the beginning of my script for it to work?

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