Functions - Reading Assignment

Javascript Programming
#1109

  1. How can you create a function in Javascript?
    A function is defined using the keyword function, followed its name, followed by parentheses containing the arguments of the function, followed by the body of the function with curly brackets.

  2. What is the difference between var and let in regards to scope?
    var scope exist outside a block (“global” scope), let scope only keep inside blocks (“local” scope).

  3. What is a pure function?
    A “pure” function is a function that doesn’t have any side-effects and doesn’t rely on side-effects from other code. It always produces the same value when the same inputs are put through.

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#1110
  1. How can you create a function in Javascript?
  • You can create a function by expression starting with “function”
  1. What is the difference between var and let in regards to scope?
  • “let” is not visible in the loop , while “var” is.
  1. What is a pure function?
  • A pure function is a function with no side effects and the same given input will return always the same output.
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#1111

  1. How can you create a function in Javascript? A function is created by starting an expression with the word function, including parameters () and the body {…which contains what is to be executed…};

  2. What is the difference between var and let in regards to scope? var is considered global while let is local only to the specific function or block. The binding created with let is not recognized after the }.

  3. What is a pure function? A function that will always return the same result when given the same inputs and it causes no side effects to the rest of the program. It also cannot effect anything outside of the function.

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#1112

  1. You create a function by writing an expression that starts with the keyword, function. You also need parameters, which can be one, many or none, and a body, which are brace-wrapped expressions that will be executed when the function is called.

  2. Bindings created with let are considered to have local scope and code outside a loop in which they may have been created cannot see them. However, bindings created with var are considered to have global scope and can be seen outside of a loop in which they may have been created.

  3. A pure function is a value-producing function that does not produce or rely on side effects.

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#1113

1. How can you create a function in Javascript?
To create a function in javascript you first define your code with the keyword ‘function.’ Then you create the name of your function following the keyword. The name can include letters, digits, underscores, and dollar signs, and follows the same rules for naming variables. Next, you add parentheses that include arguments called parameters. Then you open curly brackets and add the code that you want the function to execute. To make the function execute the code we must invoke the function when something calls upon the function. This occurs through a user performing a task, or when it is specifically called upon using code in javascript, or automatically if self-invoking is coded.

2. What is the difference between var and let in regards to scope?
Bindings created with let are local to only the scope of the block that they are declared in so the code before and after the loop they are in cannot see it and therefore are not affected by it. However, bindings using var are visible through the whole scope of the function they appear in and can be accessed globally. Both have their time and place for use depending on the use of the function.

What is a pure function?
A pure function is a function that does not produce side effects or rely on the side effects of other parts of the code. Instead, a pure function always produces the same value when the same argument is used repeatedly. It is constant and doesn’t do anything except produce its original value of the function’s intent.

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#1114
  1. How can you create a function in Javascript?
    either
    const add= function( x,y){ return x+y;}
    or
    function add(x,y) { return x+y;}
    or

( How would i write an arrow for this function? anyone can advise?)
const add= (x,y) => x+y
correct or wrong?

  1. What is the difference between var and let in regards to scope?
    var is global, while let is recognised only within the function

  2. What is a pure function?
    It produces the same output given the same input, and has deterministic state management element in it.

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#1115

  1. In 3 ways:
    a. const f = function (a) { “content here” }
    b. function g(a, b) { “content here”}
    c. let h = a >= “content here”

  2. var defines a variable that is used in the whole code regarles it is located inside a function or not.
    let defines a variable that is used just in the function if it is located inside it.

  3. A pure function is a specific kind of value-producing function that not only has no side effects but also doesn’t rely on side effects from other code. When called with the same arguments,
    it always produces the same value (and doesn´t do anything else).

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#1116

  1. By structuring larger programs to reduce repetition, to associate name to subprograms, and to isolate these subprograms from each others. It is derived that is a regular binding where the value of the binding is a function.

  2. Bindings declared with ‘let’ are local to the block that they’re declared in. If created inside a loop, the code before and after the loop cannot see it. Instead ‘var’ let’s it be visible throughout the whole function that it appears in, or throughout the global scope if they are not in a function.

  3. A pure function will give the same output but without side effects, given the same input.

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#1117

  • How can you create a function in Javascript?

    • stating the function keyword and name followed by parentheses.

  • What is the difference between var and let in regards to scope?

    • let is a local binding to a specific block and var can be seen as a global binding to an entire program.

  • What is a pure function?

    • A function that has no side effects and doesn’t rely on other codes side effects.
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#1118
  1. How can you create a function in Javascript?
    A function is created with an expression that starts with the keyword function
  2. What is the difference between var and let in regards to scope?
    let and const use block scoping, they are used within the function. Var is available globally in program
  3. What is a pure function?
    A function in which a applied input gives the same output every time the function is performed.
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#1119
  1. How can you create a function in Javascript?
    By keyword function followed by name and round brackets that can contain parameters, then curly brackets that contain statements.
    function name(parameters) { statements }
  2. What is the difference between var and let in regards to scope?
    let is local to the scope they are defined in.
    var is visible to the global scope
  3. What is a pure function?
    A pure function is a specific kind of value-producing function that not only has no side effects but also doesn’t rely on side effects from other code. When called with the same arguments, it always produces the same value (and doesn’t do anything else)
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#1120

  1. “A function is created with an expression that starts with the keyword function. Functions have a set of parameters and a body, which contains the statements that are to be executed when the function is called.”

  2. let is local to the block it’s created in, so if you create one inside a loop, the code before and after the loop will not be able to see it. var is visible to the entire function, or is visible globally if it’s created outside a function.

  3. A pure function is a specific kind of value-producing function that not only has no side effects but also doesn’t rely on side effects from other code.

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#1121

  1. You can create a function in Javascript by using the keyword "function. A name can then be added followed by parentheses which contain the function argument and then add the body of the function.

  2. Let is only visible within its own individual function locally whereas var can be used globally within the whole binding.

  3. A function which has no side effects and which doesn’t rely on side effects of other functions.

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#1122
  1. A function is created with an expression with the keyword “function”, which then has a set of parameters and a body.
  2. the “var” keyword can be seen across the global scope, while the “let” keyword can only be seen within the block that they are declared in.
  3. A “pure” function doesn’t have side affects and doesn’t rely on side affects from other code. It will always return the same return value.
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#1123
  1. we can create a function with the expression that starts with function Functions can have a set of or no parameters, and a body (which contains the statements that are executed when the function is called). e.g. const write = function(){ console.log("This is written text!"); }; write(); // result: This written text!
  2. Bindings declared with let are local to the block they are declared in, whereas bindings declared with var are visible throughout the whole function i.e. throughout the global scope.
  3. A pure function is a function that produces a value ( no side-effects) and does not rely on the side-effects of other code.
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#1124
  1. Basically you can declare using those methods:
  • function FunctionName (input) { body
    return }
  • const Name = function (input) {body
    return}
  • const Name = (input) => { body
    return}
  • var = you can declare a variable globaly or locally inside a function.
  • let = you can declare a variable only locally.
  1. Given the same inputs a pure function will always return the same ouput producing no external effect.
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#1125

  1. A function is created by using an expression, first use the keyword – function – then a set of parameters (can be multiple or none) and a body. The body holds statements to be executed when the function is used. The function body must be wrapped in curly braces.

  2. Bindings declared with let and const are local bindings, they can only be seen in the block they are declared in. If let is declared in a loop, the loop after it doesn’t know what let was. Var is a function binding and can be called throughout the function – not just the block. If used out of a function, var is attached to the window in a browser.

  3. A pure function produces no side effects – it doesn’t affect anything globally. It doesn’t use global bindings which values can change.
    A pure function given an input will give same output.

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#1126
  1. How can you create a function in Javascript?

function name_of_function { body_of_the_function }

  1. What is the difference between var and let in regards to scope?
    Bindings declared with let and const are in fact local to the block that they
    are declared in, so if you create one of those inside of a loop, the code before and
    after the loop cannot “see” it.
    Var is global and can bee seen by everywhere.

  2. What is a pure function?
    Pure function always produces same outputs for the same inputs and that not only
    has no side effects but also doesn’t rely on side effects from other code.

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#1127

1)a function is created with an expression function() and the following body { } to determine what the function does. as an example: const square = function(x) { return x*x}; // console.log(square(2)); == 4

Theres different ways of writing functions, still generating the same output. For example Arrow functions take a shortcut and use the sign combination “=>” to replace a few words in the function. would look like this:
const square (x) => {return x*x}; //console.log(square(2)); == 4

  1. let is inside the function block whereas var is globally.

  2. pure functions are in their own bubble, they only do what they are supposed to do and do not look outside their block/on global variables. To test a pure function you simply call it. If it wokrs in this context it will work in any context. Non Pure functions need more attention.

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#1128

1. How can you create a function in Javascript?

There are several notation types for a function:
a) By defining let or const binding referring to a function: const power = function(base, exponent) { }, where the data parameters are set up in the parenthesis, and the function statements are placed in the curly braces.

b) By using a function keyword as a start of the statement.
function square(x) { }

c) By using arrow sign => instead of the function keyword.
const power = (base, exponent) => { }

If a function only creates side effects, the data parameters will not be defined and the parenthesis will stay empty. Otherwise, we will input there the names of the variables that will be operated by function. In the curly braces, we assign certain commands to a function and if necessary create new bindings. Ther function can be normal or return: the normal function needs to be called(using the name of the function and if defined- data parameters) after the body is closed, and the return function uses the “return” keyword, after which the function immediately stops from being executed and returns the value is returned to a function caller at this stage.

2. What is the difference between var and let in regards to scope?
var style variables were used in pre-2015 ECMAScript syntax. They are treated by JS as global scoped. Instead let style variables are treated as local scoped.
3. What is a pure function?
A pure function is a type of value-producing function, that has no side effects and does not rely on any side effects from the other function or on the global bindings with unstable value.

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