Flashcards in Functions Deck (15)
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1
A Function Expresssion that prints a pizza order
const takeOrder = () => {
console.log('Order: pizza');
};
takeOrder();
2
What are parameters?
Parameters are variables in a function definition that represent data we can input into the function.
3
Function Declaration example syntax:
function bar() {
return 3;
}
bar() //3
bar //function
4
Anonymous Function Expression example syntax:
//anonymous function expression
var a = function() {
return 3;
}
//named function expression
var a = function bar() {
return 3;
}
//self invoking function expression
(function sayHello() {
alert("hello!");
})();
5
Refactor:
const multiplyByNineFifths = (celsius) => {
return celsius * (9/5);
};
const multiplyByNineFifths = celsius => celsius * (9/5);
6
Review Functions
Functions are written to perform a task.
Functions take data, perform a set of tasks on the data, and then return the result.
We can define parameters to be used when calling the function.
When calling a function, we can pass in arguments, which will set the function's parameters.
We can use return to return the result of a function which allows us to call functions anywhere, even inside other functions.
7
Which of the following demonstrates correct syntax for a function?
Which of the following demonstrates correct syntax for a function?
myFunction = () {
}
const myFunction = () => {
}
const myFunction{ () } (
)
const myFunction = {
}
const myFunction = () => {
}
8
What's the purpose of a parameter?
What's the purpose of a parameter?
To make the data the function uses visible.
To prevent the function from being called without certain variables defined.
To pass data to a function, which are then used when calling the function.
To pass data to a function, which are then used when calling the function.
9
Which of the following is a parameter in the block of code below?
let input = prompt('Enter input value');
const controlVal = input / 2 + 3;
const multiplier = (number, phase) => {
const val = number * controlVal + phase;
console.log(val);
};
Which of the following is a parameter in the block of code below?
input
number
controlVal
val
number
10
Which of the following is the correct way to call the function below?
const multiplier = (number) => {
console.log(3 * number);
};
Which of the following is the correct way to call the function below?
multiplier(5)
multiplier{5}
multiplier[5]
multiplier 5
multiplier(5)
11
What will this code print to the console?
const sleepTimer = (alarm) => {
console.log('My alarm is set for: ' + alarm);
}
sleepTimer('8:30AM');
What will this code print to the console?
My alarm is set for: undefined
My alarm is set for: sleepTimer
My alarm is set for: alarm
My alarm is set for: 8:30AM
My alarm is set for: 8:30AM
12
What will this code print to the console?
const workoutJournal = (miles, avgTime) => {
console.log('I ran ' + miles + ' miles at an average of ' + avgTime + ' per mile.');
}
workoutJournal('3');
What will this code print to the console?
I ran 3 miles at an average of undefined per mile.
Uncaught ReferenceError: avgTime is not defined.
I ran 3 miles at an average of per mile.
I ran 3 miles at an average of 7 minutes per mile.
I ran 3 miles at an average of undefined per mile.
13
Which of the following best describes what a function in JavaScript is used for?
Which of the following best describes what a function in JavaScript is used for?
A function is a reusable piece of code that takes an input, operates on it, then returns an output.
A function is used for math formulas.
A function allows for the use of mathematical operators.
A function creates new variables.
A function is a reusable piece of code that takes an input, operates on it, then returns an output.
14
How can you call this function?
const getCurrentDate = () => {
let date = new Date();
return date;
}
How can you call this function?
getCurrentDate();
const getCurrentDate();
getCurrentDate(){}
getCurrentDate(todaysDate);
getCurrentDate();
15
