What is pure JavaScript?

What is a pure function in JavaScript?

Pure Function is a function (a block of code ) that always returns the same result if the same arguments are passed. It does not depend on any state, or data change during a program’s execution rather it only depends on its input arguments.

What is the difference between pure and impure function in JavaScript?

A pure function must both be predictable and without side-effects. … An impure function is kind of the opposite of a pure one – it doesn’t predictably produce the same result given the same inputs when called multiple times, and may cause side-effects.

What is pure function example?

A function is called pure function if it always returns the same result for same argument values and it has no side effects like modifying an argument (or global variable) or outputting something. … Examples of pure functions are strlen(), pow(), sqrt() etc.

Is an example of impure function?

log() and alert() are impure functions because they have side effects (although they generate the same behavior and always return the same value for identical calls). Any function that changes the internal state of one of its arguments or the value of some external variable is an impure function.

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What is a side effect in JavaScript?

A side effect is the modification of state through the invocation of a function or expression. In order for a function or expression to have a side effect, the state it modifies should be out of its local scope. Such as passing an object by reference through functions to be mutated and performing I/O operations.

What is pure code?

Pure Code Rules (Axioms)

Pure code consists of functions that conform to these two rules: Takes inputs only from its parameters. Outputs only via its return value.

Is map a pure function?

Map is also a pure function meaning that it does not change the original array, instead, it returns a new array.

What is the side effects of impure function?

The return value of the impure functions does not solely depend on its arguments passed. Hence, if you call the impure functions with the same set of arguments, you might get different return values. For example, random( ), Date( ). They may modify the arguments which are passed to them.

Why is main () function so special?

Answer: The main function is special because it is entry point for program execution. It plays the role of door in a house. … Similarly, main function is important and compulsory as execution starts from here.

What is the difference between pure and impure matter?

Chemists define the term ‘pure’ as a chemical that is natural. This is a substance that is made up on one type of atom. If there is more than one type of atom, then that substance is called ‘impure’. For example, a glass containing just water is pure.

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