Name
Number.toPrecision( ): format the significant digits of a number â ECMAScript v3
Synopsis
number
.toPrecision(precision
)
Arguments
-
precision
The number of significant digits to appear in the returned string. This may be a value between 1 and 21, inclusive. Implementations are allowed to optionally support larger and smaller values of
precision
. If this argument is omitted, thetoString( )
method is used instead to convert the number to a base-10 value.
Returns
A string representation of number
that contains precision
significant
digits. If precision
is large enough to
include all the digits of the integer part of
number
, the returned string uses
fixed-point notation. Otherwise, exponential notation is used with
one digit before the decimal place and
precision
â1 digits after the decimal
place. The number is rounded or padded with zeros as
necessary.
Throws
- RangeError
If
digits
is too small or too large. Values between 1 and 21, inclusive, will not cause a RangeError. Implementations are allowed to support larger and smaller values as well.- TypeError
If this method is invoked on an object that is not a Number.
Example
var n = 12345.6789; n.toPrecision(1); // Returns 1e+4 n.toPrecision(3); // Returns 1.23e+4 n.toPrecision(5); // Returns 12346: note rounding n.toPrecision(10); // Returns 12345.67890: note added zero
See Also
Number.toExponential( )
,
Number.toFixed( )
, Number.toLocaleString( )
, Number.toString( )
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