Introduction to the JavaScript isFinite() Method
The JavaScript isFinite() method is a global method that evaluates a given argument and returns a Boolean value that indicates whether the argument is a finite number. This method can help to validate if a value is a valid number or not. In this tutorial, we will discuss how to use the isFinite() method and when it should be used.
Syntax of the JavaScript isFinite() Method
The syntax of the isFinite() method is as follows:
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isFinite(value); // returns true or false
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The isFinite() method takes one argument: the value to be evaluated. This argument can be any type of value, including a string, number, Boolean, null, undefined, and so on.
Examples of the JavaScript isFinite() Method
Let’s look at some examples of how the isFinite() method can be used.
The following example evaluates the number 42 and returns true:
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isFinite(42); // returns true
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The following example evaluates the string “42” and returns false:
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isFinite("42"); // returns false
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The following example evaluates the boolean value true and returns false:
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isFinite(true); // returns false
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The following example evaluates the value null and returns false:
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isFinite(null); // returns false
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The following example evaluates the value undefined and returns false:
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isFinite(undefined); // returns false
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The following example evaluates the value Infinity and returns false:
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isFinite(Infinity); // returns false
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When to Use the JavaScript isFinite() Method
The isFinite() method can be used to validate if a given value is a valid number or not. This can be useful when working with user input or when working with numbers that could be interpreted as strings. It can also be used to determine whether a number is within a certain range or not.
It is important to note that the isFinite() method will return true for any number that is not Infinity, -Infinity, or NaN. This means that it will also return true for non-numeric values, such as strings and booleans.
Conclusion
In this tutorial, we discussed the JavaScript isFinite() method. We discussed the syntax of the method and looked at some examples. We also discussed when it should be used and what it returns.
The isFinite() method can be a useful tool when validating user input or when working with numbers that could be interpreted as strings. It is important to note that the isFinite() method will return true for any number that is not Infinity, -Infinity, or NaN.
