Functions - Reading Assignment

Javascript Programming
#768

  1. A function is created with an expression that starts with the keyword function . Functions have a set of parameters (in this case, only x ) and a body , which contains the statements that are to be executed when the function is called. The function body of a function created this way must always be wrapped in braces, even when it consists of only a single statement.

  2. “let” is local to the block they are declared in. Any code before and after the loop cannot see it. The new scope was created with “var”, which is visible throughout the whole function that they appear in or throughout the global scope, if they are not in a function.

  3. A pure function has the pleasant property that, when called with the same arguments, it always produces the same value (and doesn’t do anything else).

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#769
  1. How can you create a function in Javascript?
  • A function can be created by writing an expression starting with the keyword “function”
  1. What is the difference between var and let in regards to scope?
  • “var” is a global binding and its scope is that its visible to the entire program and you can call it wherever you want, while “let” is used as a local binding and its scope is that its only visible and can be called within the function or block in which it is situated in
  1. What is a pure function?
  • A pure function is a specific value producing function that has no side effects and no need for side effects from other code. It can be tested simply by calling it and working in its own context
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#770
  1. With the nomenclature string = function(binding)
  2. let is only ‘seen’ within its own scope, whereas var is seen in the global scope.
  3. A pure function always recalls the same value.
#771

1.) A function is created with an expression that starts with the keyword function.
2.) This difference between let and var is that let is local to the block that function is declared in. In Pre-2015 java script functions created with var are visible “through out the hole function they appear in- or throughout the global scope if they are not 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—for
example, it doesn’t read global bindings whose value might change. A pure
function has the pleasant property that, when called with the same arguments,
it always produces the same value.”

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#772

  1. With an expression starting with the keyword function containing a set of parameters and a body. The body contains the statements to be executed when the function is called and must always be wrapped in braces, whether it consists of multiple parameters or no parameters at all.

  2. Each binding has a scope - the part of the program in which the binding is visible. For bindings defined outside of any function or block (global binding), the scope is the whole program. These bindings can be referred to wherever, but bindings created for function parameters, or declared inside a function, can be referenced only in that function (local bindings). Every time the function is called, new instances of these bindings are created in its own little context (the local environment). Bindings declared as let and const are local to the block they are declared in. Inside a loop, the code before and after the loop cannot see it. Var were old-style bindings and visible throughout the whole function - the global scope - if not in a function.

  3. Pure function - value-producing function with no side effects. Also doesn’t rely on side effects from other code, like global bindings whose value might change. A pure function is called with the same arguments and always produces the same value. Its return value can be substituted without changing the meaning of the code. Can be tested by calling it to see if it works in that context, then it’ll work in any context.

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#773
  1. Function is created by using the keyword ‘function’. It can take in additional parameters between ‘()’ and has a body between ‘{}’.
  2. ‘Var’ has a global scope (unless declared within a function), while ‘let’s’ scope is within the block is has been declared in.
  3. Pure function is a function that returns values and given the same arguments will always produce the same result, because it doesn’t rely on any outside side effects.
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#774
  1. function (a, b) { a + b };
  2. Let is small in scope and local to the block where it’s created, such as inside a function. Var defines the variable globally, or locally to an entire function.
  3. A pure function is a function that given that same input will always return the same output, and produces no side effects. It doesn’t affect global bindings.
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#775

  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.
    The function body of a function created this way must always be wrapped in
    braces, even when it consists of only a single statement.

  2. 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. In pre-2015 JavaScript, only functions created
    new scopes, so old-style bindings, created with the var keyword, are visible
    throughout the whole function that they appear in—or throughout the global
    scope, if they are not in a function.

  3. A pure function is a function which: Given the same input, will always return the same output. Produces no side effects.

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#776

  1. How can you create a function in Javascript?
    You can create a function with expression starting with the keyword function to create new vocabulary. It contains a set of parameters and a body.

  2. What is the difference between var and let in regards to scope?
    There are two types of scope in Javascript, global and local. Global scope means that the Var is visible for the entire coding. Local scope on the other hand, Var is only visible inside of the function. Let only works within the function, hence only works in Local scope.

  3. What is a pure function?
    A pure function means that there are no side effects and it’s deterministic that always produces the same value.

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#777
  1. First open the function by typing “function()”, Secondly giving it an explanatory name, thirdly name the values that the function is requesting.
    Example:
    function square(x) {
    return x * x;
    }

In this example the function also contains an expression which it also returns.

  • var is Global scope if it’s outside a funciton, and visible inside of the function if created within it.
  • let is only visible in the block that it’s created in, it will not be visible before or after that block.
  1. A pure function requires no external values, isn’t dependent on side effects nor produces side effects, it only requires the code that is inside of it.
    Such a function will always return the same kind of value, no matter of where in the code it is implemented.
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#778

  1. How can you create a function in Javascript?
    You create a function by using the keyword function followed by the body or parameters inside of () that contain the statements for execution.

  2. What is the difference between var and let in regards to scope?
    Var is known throughout the entire function body parameter, and let is only known throughout the block that it is in.

  3. What is a pure function?
    A pure function is a function that does not rely on side effects, and produces the same value every time that it is called for as long as the argument is unchanged, and it doesn’t do anything else.

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#779
  1. A function is created with an expression that starts with keyword function.
  2. Var is visible throughout the whole function that they are used in or throughout the global scope if they are used outside a function. Let is local to the block that it is created in.
  3. Pure function means, that wherever you use it and whenever you give it the same inputs it will always return same value.
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#780

  1. A function is created with an expression that starts with the keyword function.

  2. Bindings declared with let and const are in fact local to the block that they
    are declared in, but var is accessible globally without considering the block scope.

  3. A pure function is a function where the return value is only determined by its input values, without observable side effects.

#781

  1. A function is created with an expression that start 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. 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 a loop, the code before and after the loop cannot “see” it. Bindings created with the var keyword are visible throughout the whole function that they appear in, or throughout the global scope, if they are not in 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 for example it doesn’t read global bindings whose value might change.

#782

  • How can you create a function in Javascript?
    Your start with the function keyword followed by the name of the function , then a list of parameters between the parentheses (comma-separated, or empty) and finally the code of the function / the function body, between curly braces.
    function mymessage () {
    alert (“Welcome to my World!”);
    }
    mymessage();

  • What is the difference between var and let in regards to scope?
    Variables that are declared with var , are either function-scoped or global-scoped and are visible through blocks.
    If variables are defined with ‘let’ inside a function they are not accessible (visible) from outside the function.

  • What is a pure function?
    A pure function is a function which will always return the same output given the same input. It depends only on its own arguments and does not try to change variables out of its scope. Also it does not produce any side effects.

#783
  1. by declaring one and naming it’s parameters
  2. var is visible outside the local function location while let is not.
  3. A function that does not rely on using a side effect to return a value.
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#784

How can you create a function in Javascript?
a function is defined using the function keyword followed by the function name, arguments and code

What is the difference between var and let in regards to scope?
“let” define local variables
“var” defines global variables

What is a pure function?
one with no side effect(s) and which does not rely on effects from code external to the function

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#785

  1. It’s created with an expression, using the keyword function.
    Example: const myfirst = function ( ) { // statement to be executed / body
    }

  2. var can either be global or local to a function.
    let is only local to a block

  3. Using the same arguments, a pure function always gives the same result without producing any side effect.

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#786
  1. How can you create a function in Javascript?
    p.39 A function is created with an expression that starts with the keyword function
    . Functions have a set of parameters (in this case, only x) and a body, which
    contains the statements that are to be executed when the function is called.
  2. What is the difference between var and let in regards to scope?
    p.41 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. In pre-2015 JavaScript, only functions created
    new scopes, so old-style bindings, created with the var keyword, are visible
    throughout the whole function that they appear in—or throughout the global
    scope, if they are not in a function
  3. What is a pure function?
    p.54 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—for
    example, it doesn’t read global bindings whose value might change. A pure
    function has the pleasant property that, when called with the same arguments,
    it always produces the same value (and doesn’t do anything else).
1 Like
#787
  • You can create a function in JavaScript with an expression that begins with the keyword function. Functions have parameters and a body which contains the statements the function will carry out.
  • The differences between var and let. Let is a local function, it cannot be seen outside of its loop. Var is a global function which can be seen throughout the whole function or outside of a function.
  • A pure function is a basically a mathematical function. It’s return value (output) will always be the same given the same inputs. A pure function has no side effects, it does not cause any change to the overall program.
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