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157

How do you represent a number as a string in javascript?

rated 0 times [ 164] [ 7] / answers: 1 / hits: 16059 / 7 Years ago, mon, january 30, 2017, 12:00:00

I have a node-red flow that needs to create an MQTT payload.

The payload is a temperature reading from an I/O card, calculated as a float (73.4 for example).

I need the message payload to be a string, not a number; something like Barn Temp is 73.2. How can I create this?

msg.payload = tempReading;               // gives a number

msg.payload = +tempReading;            // returns NaN

A bonus question: if I did use this as a numeric payload how can I specify its format? The reading is calculated at 73.18527461364; I need to send this as 73.2.

I'm having a devil of a time finding out how to format strings in javascript!

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johnnaj

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4 Years ago

answered 7 Years ago masonm · Accepted Answer

toString is an easy surefire way to convert numbers to strings.

var x = 10.56;

x = x.toString();

console.log(x, typeof x);

If you want to control how many decimal points are displayed, you can use toFixed.

var x = 12.3456789;

x = x.toFixed(3);

console.log(x, typeof x);