The syntax of the toPrecision() method is:
num.toPrecision(precision)
Here, num is a number.
Number toPrecision() Parameters
The toPrecision() method takes in:
- precision (Optional) - An integer specifying the number of significant digits
Notes:
- If precision is omitted, it behaves as Number.toString() and the entire number is returned.
- If precision is a non-integer value, it is rounded to the nearest integer.
Return value from Number toPrecision()
- Returns a
String, representing a number rounded to precision significant digits.
Note: The toPrecision() method throws a RangeError if precision is not in between 1 and 100.
Example: Using Number.toPrecision()
let num = 57.77583;
console.log(num.toPrecision()); // 57.77583 -> similar to toString()
console.log(num.toPrecision(5)); // 57.776
console.log(num.toPrecision(2)); // 58
console.log(num.toPrecision(1)); // 6e+1 -> in somecases, exponential notation
num = 0.000123;
console.log(num.toPrecision()); // 0.000123
console.log(num.toPrecision(5)); // 0.00012300
console.log(num.toPrecision(2)); // 0.00012
console.log(num.toPrecision(1)); // 0.0001
Output
57.77583 57.776 58 6e+1 0.000123 0.00012300 0.00012 0.0001
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