The toPrecision()
method returns a string representing the Number object to the specified precision.
numObj.toPrecision([precision])
precision
A string representing a Number object in fixed-point or exponential notation rounded to precision
significant digits. See the discussion of rounding in the description of the numObj.toFixed() method, which also applies to toPrecision()
.
If the precision
argument is omitted, behaves as numObj.toString(). If the precision
argument is a non-integer value, it is rounded to the nearest integer.
precison
is not between 1 and 100 (inclusive), a RangeError is thrown. Implementations are allowed to support larger and smaller values as well. ECMA-262 only requires a precision of up to 21 significant digits.toPrecision
var numObj = 5.123456; console.log(numObj.toPrecision()); // logs 5.123456 console.log(numObj.toPrecision(5)); // logs 5.1235 console.log(numObj.toPrecision(2)); // logs 5.1 console.log(numObj.toPrecision(1)); // logs 5 // note that exponential notation might be returned in some circumstances console.log((1234.5).toPrecision(2)); // logs 1.2e+3
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