typescript - convert string to number

Question

totalbalancetemp = (Number(this.balance)) + (Number(this.pastAmount));

My totalbalancetemp is returning undefined whereas this.balance is equal to 34 and this.pastAmount is equal to 23.

I have this in controller and displaying totalbalancetemp using exp in html

• Thirueswaran Rajagopalan: if totalbalancetemp is a property of the component. then shouldn't you call it by this.totalbalancetemp

Answer 1

Supply the proper type.

let totalbalancetemp:number = balance + pastAmount

This will throw an error, because you are now guaranteeing that totalbalancetemp will be a number.

The type String is not assignable to type 'number'

Try the following:

let balance:string = '34',
 pastAmount:string = '23',
 totalbalancetemp:number = 0
totalbalancetemp = Number(balance) + Number(pastAmount)
alert(totalbalancetemp)

• john: It is still giving me 0 as totalbalancetemp and not adding these values actually balance is like from json like this.payment.total and this.payment.pastAmount

Answer 2

totalbalancetemp = (Number(this.balance)) + (Number(this.pastAmount));

please try this it should work

totalbalancetemp:number = (+this.balance) + (+this.pastAmount);

Answer 3

var totalbalancetemp = null; this.balance = 34; this.pastAmount = 23; 
totalbalancetemp = (Number(this.balance)) + (Number(this.pastAmount));
alert(totalbalancetemp);

-->totalbalancetemp - Define Variable (or) any type

Answer 4

totalbalancetemp should be replaced by this.totalbalancetemp if it's part of the angular 2 component

Answer 5

Do a +this.balance in the .ts file or this.balance*1 or this.balance/1 on in the template file.