How to convert a number to double data type in javascript/ typescript?

Question

I have one input filed where the user can enter any numbers eg: 12 12.1 12.30 12.34 I have to pass this value in a service call here i can only send the value as number but with 2 decimal points

let a = input //a will be a type of number
let b = a.toFixed(2) //b will be type of string
let c = Number(b) //it will automatically cut unwanted '0'
console.log(c);

EXAMPLE

//input is 12
a=12
b="12.00"
c=12

//input is 12.30
a=12.30
b="12.30"
c=12.3

I want a method, using which i can input a value as a number and output will be number with 2 decimal points.

All numeric types in typescript are number which are floating point values, so I don't think data type conversion is what you're after here. Seems like you just want to take any number and round/truncate it or right-pad w/ zeroes to two digits. typescriptlang.org/docs/handbook/basic-types.html — JBC
– JBC, Commented Jul 28, 2017 at 21:40
You can try getting the value of your input, parseFloat it and then toFixed it — Lixus
– Lixus, Commented Jul 28, 2017 at 21:42
"Double" does not mean two decimal places, it means double precision. There is no way to specify a number to a fixed number of places except to store it as a string using .toFixed. That's the whole reason that method returns a string in the first place. — Jared Smith
– Jared Smith, Commented Jul 28, 2017 at 21:49
Actually, you may want to use toExponential method, so you can store your 12.30 number as 1230e-2 and don't loose that zero. — Maxim Mazurok
– Maxim Mazurok, Commented Jul 28, 2017 at 21:56

bpjoshi · Accepted Answer · 2017-07-28 21:52:50Z

2

If you want a number to always display in two decimal places, you can do as below. It will round all the numbers to two decimal places(including doubles).

function twoDecimal(yourNumber){
    return parseFloat(Math.round(yourNumber * 100) / 100).toFixed(2);
}

let x=twoDecimal(10);

answered Jul 28, 2017 at 21:52

bpjoshi

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Aswin KV Over a year ago

gyazo.com/17f167b50ba7c719ec3f2616e045cf1a go through the above screenshot I had input the value as number :12 after this (Math.round(yourNumber * 100) / 100).toFixed(2) value changed to= "12.00" but after parseFolat() the value changed to 12 My objective is if i gave 12(type number) i want to get output/return as 12.00(type of number).

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