I searched and only found this one related to my question, but not exactly the same, as I'm using toFixed rather than toPrecision. Why does toPrecision return a String?
Here is my code
var oldv = parseFloat(document.getElementById('total').textContent).toFixed(2);
alert(typeof oldv); // returns string
var testv = parseInt(document.getElementById('total').textContent);
alert(typeof testv); // returns number
I need further math steps, so string type messed up... Why? How to solve? TIA
The parseFloat() function parses an argument (converting it to a string first if needed) and returns a floating point number.
The parseFloat() function is used to accept the string and convert it into a floating-point number. If the string does not contain a numeral value or If the first character of the string is not a Number then it returns NaN i.e, not a number.
JavaScript provides two methods for converting non-number primitives into numbers: parseInt() and parseFloat() . As you may have guessed, the former converts a value into an integer whereas the latter converts a value into a floating-point number.
As mentioned in docs, toFixed
returns
A string representing the given number using fixed-point notation
In case you need to use the returned result as a number, you can use built-in object Number
:
var oldv = parseFloat(Math.PI).toFixed(2);
console.log( oldv );
console.log( typeof oldv ); // returns string
var num = Number(oldv);
console.log( num );
console.log( typeof num ); // returns number
The Number.prototype.toFixed() function is supposed to return a string type as per the documentation found here.
If you need to perform further arithmetic with the number you can coerce it back into numeric form using the Unary plus operator before the variable name (+) documented here like so:
var oldv = parseFloat(document.getElementById('total').textContent).toFixed(2);
alert(typeof oldv); // Returns string
alert(typeof +oldv); // Returns number
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