javascript - Replace() yields "Uncaught TypeError: undefined is not a function" when used with zero -

i'm getting numbers mongodb, parse them format removing space or comma if exists using replace() method. while working while, found producing following error when value zero

uncaught typeerror: undefined not function 

the snippet include questioned method follows:

function query_member_points_credits_summaryexecute()  {     var balance = apperyio.storage.ms_member_points_credits_summary.get("$['balance']");     var balance = parsefloat(balance.replace(',', '').replace(' ', ''));     console.log("balance " + balance);     var threshold = parsefloat(50000);     console.log("threshold " + threshold); } 

the error caused second line.

investigation attempts:

1. i replaced line following:
   a. var balance = parsefloat(balance.replace(',', ''));
   b. var balance = parsefloat(balance.replace(' ', ''));
   c. var balance = balance.replace(',', '').replace(' ', '');

2. only has worked balance = 0:
   var balance = parsefloat(balance);

3. using numbers other zero, including 0.000001, working fine

i'm baffled reason

i first suggest, after:

var balance = apperyio.storage.ms_member_points_credits_summary.get("$['balance']"); 

putting in debug code tell balance is, like:

alert(typeof(balance)); 

from error message, it's possibly undefined. if case, need track down why appery.io giving undefined value zero.

if it's not undefined, may strange type (i.e., not string) may affect pipeline of replace calls.

if appery.io giving number type 0 , string type non-zero (as per comment), quick'n'dirty fix may like:

// ensure number made string before replace. var balance = parsefloat((""+balance).replace(',', '').replace(' ', '')); 

then i'd contacting them ask whether bug on part.