In this article, you’ll learn 12 JavaScript Number methods that you should know.
1. parseInt() Method
The parseInt() method parses the given string argument and returns an integer number parsed from the string.
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If an integer can’t be parsed from the given string, the method returns NaN.
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2. toString() Method
The toString() method returns the given number in the form of a string. This method accepts radix (the base in mathematical numeral systems) as an optional parameter and returns a string representing the specified Number object.
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3. toExponential() Method
The toExponential() method returns a string that represents the exponential notation of the given number. This method accepts fractionDigits as an optional parameter that specifies the number of digits after the decimal point.
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4. toFixed() Method
The toFixed() method returns a string that represents a number formatted using fixed-point notation. This method accepts an optional parameter that specifies the number of digits to appear after the decimal point. If no parameter is provided, the value of this parameter is treated as 0.
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5. toPrecision() Method
The toPrecision() method returns a string representing the number to the specified precision. This method accepts an optional parameter that specifies the number of significant digits.
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6. valueOf() Method
The valueOf() method returns the primitive value of a Number object.
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7. toLocaleString() Method
The JavaScript toLocaleString() method returns a string with a language-sensitive representation of a number.
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8. parseFloat() Method
The parseInt() method parses the given string argument and returns a floating-point number parsed from the string.
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If a number can’t be parsed from the given string, the method returns NaN.
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9. isInteger() Method
The isInteger() method checks whether the passed value is an integer. This method returns a Boolean value (true or false) that indicates whether the given value is an integer or not.
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10. isFinite() Method
The isFinite() method checks whether the passed value is a finite number. This method returns a Boolean value (true or false) that indicates whether the given value is finite or not.
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11. isSafeInteger() Method
The isSafeInteger() method checks whether a value is a safe integer. This method returns a Boolean value (true or false) that indicates whether the given value is a safe integer or not.
According to the official MDN Docs, a safe integer is an integer that:
can be exactly represented as an IEEE-754 double-precision number, and whose IEEE-754 representation cannot be the result of rounding any other integer to fit the IEEE-754 representation.
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12. isNaN() Method
The isNaN() method checks whether a value is a NaN and its type is Number. This method returns true if the given value is NaN and its type is Number, otherwise, it returns false.
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If you want to have a look at the complete source code used in this article, check out the GitHub repository.
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