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What is the infinity global property in Javascript and when is it used?
In JavaScript, the Infinity global property represents a mathematical concept of infinity. It is a special value that represents a number that is greater than any other number.
The Infinity property is typically used in computations involving large numbers or mathematical operations that result in a value that is too large to be represented by a standard number data type. It can also be used to check if a number is infinite using the isFinite() function.
For example:
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console.log(1 / 0); // Output: Infinity
console.log(Infinity + 1); // Output: Infinity
console.log(Infinity * 10); // Output: Infinity
console.log(Infinity === Infinity); // Output: true
console.log(isFinite(Infinity)); // Output: false
It's important to note that dividing a non-zero number by Infinity or performing operations involving Infinity may result in unexpected and non-numeric values.
property infinity
Infinity is a property in JavaScript that represents the mathematical infinity value. It is a globally defined variable that represents a numeric value greater than any other number. Here's an example:
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console.log(Infinity); // Output: Infinity
console.log(10/0); // Output: Infinity
console.log(-10/0); // Output: -Infinity
👩💻 - infinity
Negative Infinity -Infinity is the opposite of Infinity. It is a globally defined variable in JavaScript representing a numeric value less than any number. Here's an example:
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console.log(-Infinity); // Output: -Infinity
console.log(-10/0); // Output: -Infinity
console.log(10/-0); // Output: -Infinity
👩💻 nan
In JavaScript, NaN stands for 'Not a Number' and it is a value representing an undefined or unrepresentable value resulting from an arithmetic operation. It's typically the result of dividing a number by zero or performing other mathematical computations that don't produce a meaningful result. Here's an example:
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console.log(0 / 0); // Output: NaN
console.log(Math.sqrt(-1)); // Output: NaN
console.log(parseInt("hello")); // Output: NaN
It's important to note that NaN is not equal to any value, including itself, so you cannot use standard operators like == and === to compare it to other values. To check if a value is NaN, you can use the isNaN() function.
👩💻 isFinite()
isFinite() is a built-in function in JavaScript that determines whether a given value is a finite number. It returns true if the value is a finite number, false if the value is NaN, Infinity, or -Infinity. Here's an example:
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console.log(isFinite(3)); // Output: true
console.log(isFinite(Infinity)); // Output: false
console.log(isFinite(-Infinity)); // Output: false
console.log(isFinite(NaN)); // Output: false
console.log(isFinite("hello")); // Output: false
isFinite() is often used to validate user input to ensure that a value is a valid number.
👩💻 isNaN()
isNaN() is a built-in function in JavaScript that determines whether a value is NaN or not. It returns true if the value is NaN, false if the value is a number or can be converted to one. Here's an example:
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console.log(isNaN(NaN)); // Output: true
console.log(isNaN(10)); // Output: false
console.log(isNaN('Hello')); // Output: true
console.log(isNaN('10')); // Output: false
It's important to note that isNaN() will attempt to convert non-numeric values into numeric values before checking if it is NaN. For example, isNaN('Hello') will return true because 'Hello' cannot be converted into a numeric value. However, isNaN('10') will return false because '10' can be converted into a numeric value of 10. To avoid this confusion, you can use the dedicated function Number.isNaN() introduced in ECMAScript 2015 (ES6). It only returns true if the value is NaN and does not perform any type coercion.
👩💻 infinite number
There is no specific data type for infinite numbers in JavaScript. Instead, it uses the Infinity global property to represent positive infinity and the -Infinity global property to represent negative infinity. Here are some examples:
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console.log(Infinity); // Output: Infinity
console.log(-Infinity); // Output: -Infinity
console.log(1 / 0); // Output: Infinity
console.log(-1 / 0); // Output: -Infinity
You can perform arithmetic operations with infinity values, such as adding or subtracting them from other numbers. However, certain operations like dividing Infinity by Infinity will result in NaN.
👩💻 Difference between == and ===
== and === are both comparison operators in JavaScript used to compare two values.
== is the equality operator and compares two values for equality. It performs type coercion, which means that if the types of the two values being compared are not the same, JavaScript will try to convert one or both of them to the same type before making the comparison. For example:
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console.log(5 == '5'); // Output: true
console.log(0 == false); // Output: true
console.log('' == false); // Output: true
=== is the strict equality operator and compares two values for both type and value equality. It does not perform type coercion, which means that if the types of the two values being compared are not the same, the operator will return false. For example:
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console.log(5 === '5'); // Output: false
console.log(0 === false); // Output: false
console.log('' === false); // Output: false
It's generally recommended to use === instead of == whenever possible, since it can help prevent bugs caused by unexpected type coercion. However, there are cases when == may be useful, such as when checking for null or undefined values.
👩💻 Explain this console.log('' == false); // Output: true
In JavaScript, the == operator performs type coercion, which means that if the types of the two values being compared are different, JavaScript will try to convert one or both of them to the same type before making the comparison.
In this case, '' is an empty string, which is a falsy value in JavaScript. false is also a falsy value. Since the types of the two values are different, JavaScript will try to convert them to the same type before comparison.
In this case, the empty string '' is coerced into a number, which gives us 0. The false value is also coerced into a number, which also gives us 0. Since 0 == 0, the comparison evaluates to true.
It's worth noting that using the === operator instead of == would give us a different result, since === does not perform type coercion. In this case, '' === false would evaluate to false, since '' is a string and false is a boolean, and they are not the same type.
👩💻 falsy value
In JavaScript, a falsy value is a value that is considered false when encountered in a Boolean context. The following values are falsy in JavaScript:
false0 (numeric zero)'' or "" (empty string)nullundefinedNaNHere's an example that demonstrates how falsy values work in JavaScript:
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if (false) {
console.log('This code will not run.');
}
if ('') {
console.log('This code will not run.');
}
if (0) {
console.log('This code will not run.');
}
if (null) {
console.log('This code will not run.');
}
if (undefined) {
console.log('This code will not run.');
}
if (NaN) {
console.log('This code will not run.');
}
In each case, the condition in the if statement evaluates to false, so the code block within the if statement is not executed.
👩💻 modulo (%) operator
The modulo operator (%) in JavaScript is a mathematical operator that returns the remainder of dividing two numbers. If the dividend is not evenly divisible by the divisor, the remainder will be a positive number less than the divisor. If the dividend is evenly divisible by the divisor, the remainder will be zero.
Here are some examples:
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console.log(5 % 2); // Output: 1 (since 5 divided by 2 has a remainder of 1)
console.log(10 % 5); // Output: 0 (since 10 divided by 5 has no remainder)
console.log(8 % 3); // Output: 2 (since 8 divided by 3 has a remainder of 2)
The modulo operator is often used in programming to perform operations that depend on whether a number is even or odd (by checking if the remainder when dividing by 2 is 0 or 1, respectively) or to perform an action every n iterations of a loop (by checking if the remainder when dividing the current iteration count by n is 0).
👩💻 console.log(3**3);
The ** operator in JavaScript is the exponentiation operator. It is used to raise a number to a given exponent. The syntax is base ** exponent. Here's an example:
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console.log(3 ** 3); // Output: 27 (since 3 raised to the power of 3 equals 27)
In this case, 3 is the base and 3 is the exponent, so 3 ** 3 returns 27.
👩💻 postfixing and prefixing
Postfix and prefix are terms used to describe the position of an operator in relation to its operands.
Prefix: When an operator is placed before its operand(s), it is said to be a prefix operator. For example, in the expression -3, the - operator is placed in front of the operand 3 and is therefore a prefix operator. Another example of a prefix operator is the typeof operator, which returns a string indicating the type of its operand.
Postfix: When an operator is placed after its operand(s), it is said to be a postfix operator. For example, in the expression x++, the ++ operator is placed after the operand x and is therefore a postfix operator. Another example of a postfix operator is the array access operator [], which is used to access an element of an array.
The main difference between postfix and prefix operators is when they are evaluated. Prefix operators are evaluated before their operands, while postfix operators are evaluated after their operands.
It's worth noting that some operators, such as + and -, can be used as both prefix and postfix operators in some contexts. For example, in the expression ++x, the ++ operator is a prefix operator, while in the expression x++, the ++ operator is a postfix operator.
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