JS Operators & Misc Grammar Flashcards Preview

Javascript is a Language > JS Operators & Misc Grammar > Flashcards

Flashcards in JS Operators & Misc Grammar Deck (38):
1

delete Operator

delete person.age;

deletes a property from an object

2

in Operator

"firstName" in person
4 in array

returns true if the specified property is in the specified object, otherwise false

3

instanceof Operator

cars instanceof Array

returns true if the specified object is an instance of the specified object

4

break ?labelname;

use with label:
Loop2:
for (j = 10; j < 15; j++) {
if (j === 12) {
break Loop2;
}
}

exits a switch statement or a loop (for, for ... in, while, do ... while)

5

continue ?labelname

breaks one iteration (in the loop) if a specified condition occurs, and continues with the next iteration in the loop

6

debugger

enter debugging mode

7

do...while

creates a loop that executes a block of code once, before checking if the condition is true, then it will repeat the loop as long as the condition is true

8

for (statement 1; statement 2; statement 3) {
code block to be executed
}

creates a loop that is executed as long as a condition is true

9

for (var in object) {
code block to be executed
}

for (x in person) {
text += person[x];
}

loops through the properties of an object.

The block of code inside the loop will be executed once for each property.

10

return value;

stops the execution of a function and returns a value from that function

11

switch(expression) {
case n:
code block
break;
case n:
code block
break;
default:
default code block
}

executes a block of code depending on different cases

12

while (condition) {
code block to be executed
}

creates a loop that is executed while a specified condition is true

13

Math.E

Returns Euler's number (approx. 2.718)

14

Math.LN2

Returns the natural logarithm of 2 (approx. 0.693)

15

Math.LN10

Returns the natural logarithm of 10 (approx. 2.302)

16

Math.LOG2E

Returns the base-2 logarithm of E (approx. 1.442)

17

Math.LOG10E

Returns the base-10 logarithm of E (approx. 0.434)

18

Math.PI

Returns PI (approx. 3.14)

19

Math.SQRT1_2

Returns the square root of 1/2 (approx. 0.707)

20

Math.SQRT2

Returns the square root of 2 (approx. 1.414)

21

Math.abs(x)

Returns the absolute value of x

22

Math.acos(x)

Returns the arccosine of x, in radians

23

Math.asin(x)

Returns the arcsine of x, in radians

24

Math.atan(x)

Returns the arctangent of x as a numeric value between -PI/2 and PI/2 radians

25

Math.atan2(y,x)

Returns the arctangent of the quotient of its arguments

26

Math.ceil(x)

Returns x, rounded upwards to the nearest integer

27

Math.cos(x)

Returns the cosine of x (x is in radians)

28

Math.exp(x)

Returns the value of E^x

29

Math.floor(x)

Returns x, rounded downwards to the nearest integer

30

Math.log(x)

Returns the natural logarithm (base E) of x

31

Math.max(x,y,....)

Returns the number with the highest value

32

Math.min(x,y,...)

Returns the number with the lowest value

33

Math.pow(x,y)

Returns the value of x to the power of y

34

Math.random()

Returns a random number between 0 and 1

35

Math.round(x)

Rounds x to the nearest integer

36

Math.sin(x)

Returns the sine of x (x is in radians)

37

Math.sqrt(x)

Returns the square root of x

38

Math.tan(x)

Returns the tangent of an angle