Data Types

Consider the following example:

console.log(0.1 + 0.2 == 0.3)

This outputs false as division by 10 in binary is not representable fully just like 1/3 in decimals. Although, going with the same logic powers of 2 will work fine.

ToFixed

ToFixed(number of digits) always returns a string used to round of to some number of digits

isNaN

Interesting thing about JavaScript:

alert( NaN === NaN ); // false

This is in the sense that, JavaScript considers NaN to be uniqueq that is it not equal to anything, including itself. This can considered somewhat like the Symbols where every symbol created is uniqe.

q: What will happen when NaN is taken as a key for an object?

so, one can use the function isNaN to check if the given argument after converting to a number primitive data type is NaN or not.

isFinite

Another method like isNaN which also filters out Infinity and -Infinity.

Object.is(a, b)

This checks the data types bit by bit intutively, it is equivalent to === apart from the case when input is (0, -0) and (NaN, NaN).

+ and Number()

The numeric conversion is strict for this case, when compared to parseInt method which also takes in second argument as the radix (the base in which the first argument is to be parsed in).

Math library

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math

Some special mentions

Math.random()

This return a number in the range [0, 1).