Syntax intro Flashcards
What is a template literal?
String literal that adds to expressions through interpolation.
Denoted by “ ` “ the backtick.
const myPet = 'armadillo';
console.log(`I own a pet ${myPet}.`);
// Output: I own a pet armadillo.
What are template literals wrapped with?
Backticks.
`
What operator is useful to check the data type of a variable’s value?
typeof
What are strings wrapped with?
Apostrophes.
What is the preferred way to declare a variable when it can be reassigned?
let
What is the preferred way to declare a variable with constant value?
const
What is the primitive data type of variables that have not been initialized?
undefined
what operator is used to consecrate strings?
+
What is a Method?
Methods return information about an object, and are called by appending an instance with a period ., the method name, and parentheses.
return a floating-point, random number in the range from 0 (inclusive) up to but not including 1.
Math.random()
return the largest integer less than or equal to the given number.
Math.floor()
intentional absense of value
null
Modulo
%
finds the remainder
10 % 5
single line comment
//
multi line comment
/* */
What is faster ABOVE 30 substrings, interpolation or concatenation?
Interpolation
What is faster BELOW 30 substrings, interpolation or concatenation?
Concatenation
CON CAT E NATION
method that finds length of a string
.length
Is equal to
===
or operator
||
Checked FIRST || LAST
truthy or falsy?
Empty strings like “” or ‘’
falsy
truthy or falsy?
‘Elliott’
Truthy.
NaN
Not a number
Ternary operator operators
? : ;
isLocked ? console.log(‘You will need a key to open the door.’) :
console.log(‘You will not need a key to open the door.’);
Proper order?
A. else (){} if (){} else if
B. if (){} else (){} else if
C. if (){} else if (){} else
if / else if / else
what is a switch statement
A switch statement provides an alternative syntax to else if that is easier to read and write. A switch statement looks like this:
switch (…) {
case ‘…’ :
ANYFUNCTION( );
break;
case 'lime':
console.log('Limes are $1.49');
break;
case 'papaya':
console.log('Papayas are $1.29');
break;
default:
console.log('Invalid item');
break;
}
break
tells the computer to exit the block and not execute any more code or check any other cases inside the code block.
default
at the end of a switch statement, is the default outcome if all else fails.
What will a switch statement do without a break?
the first matching case will run, but so will every subsequent case regardless of whether or not it matches—including the default.
Bang operator
The bang operator, !, switches the truthiness and falsiness of a value.
Strict inequality operator
!==
checks whether its two operands are not equal, returning in a boolean.
Control flow
order in which statements are executed in a program.
what is a condition
the enclosing brackets () after a logic statement
control flow statements
if then else etc
function
repeatable set of tasks
What comes after the function keyword?
an identifier
What is hoisting?
Accessing a function before it is called
What is hoisting?
Accessing a function before it is defined
What is hoisting?
Calling a function before it is defined
What do parameters do?
Parameters allow functions to accept input(s) and perform a task using the input(s).
Default parameters
function funtionName(parameter = 'Default Value', parameter2 = 100, parameter3 = true) {
// Function body here
}
