Eloquent Javascript: Chapter 1

Front 1

Operator

Back 1

a symbol representing a mathematical operation (+, -) or other type of operation

Front 2

Value

Back 2

A category of data

Front 3

Types of Values

Back 3

Numbers, strings, booleans, objects, functions, and undefined values

Front 4

\n, \t etc., in a string

Back 4

A backslash followed by certain characters in the middle of quoted text (a string) means that the character has special meaning. \n is new line, \t is tab. \" is quotation mark, not the end of the string.

Front 5

+ sign between strings

Back 5

Concatenates - merges (strings) together

Front 6

Binary vs. Unary Operators

Back 6

A binary operator has two operands (1+1), a unary operator has one (-2)

Front 7

Boolean

Back 7

A value that is either true or false

Front 8

x<y and y>x

Back 8

Greater or less boolean operators

Front 9

!=, <=, >=

Back 9

more boolean operators: is not equal to, less than or equal to, more than or equal to

Front 10

Logical Operators

Back 10

and (&&), or (||), not (!)
used to determine the logic between variables or values (boolean)

Front 11

Expression

Back 11

a piece of code that expresses a value
5(2+3) is an expression, as well as the number 8, the string "have a nice day" and the < > symbols

Front 12

Statement

Back 12

The basic unit of a program (a program is built as a list of statements); a larger unit than an expression. most statements end with a semicolon.

Front 13

Modulo

Back 13

The % symbol is used to represent the remainder operation. For example, 314 % 100 produces 14, and 144 % 12 gives 0.

Front 14

NaN

Back 14

Stands for "not a number”, even though it is a value of the number type. You’ll get this result when you, for example, try to calculate 0 / 0 (zero divided by zero), Infinity - Infinity, or any number of other numeric operations that don’t yield a precise, meaningful result.

Front 15

Strings

Back 15

Strings are used to represent text data types. They are written by enclosing their content in quotes. ex. "I am a string"

Front 16

Escaping the character

Back 16

Whenever a backslash (“\”) is found inside quoted text, it indicates that the character after it has a special meaning.

Front 17

Conditional/Ternary Operator

Back 17

The value on the left of the question mark “picks” which of the other two values will come out. When it is true, the middle value is chosen, and when it is false, the value on the right comes out. Ex: console.log(true ? 1 : 2); // → 1 console.log(false ? 1 : 2); // → 2

Front 18

Undefined Values

Back 18

There are two special values, written null and undefined, that are used to denote the absence of a meaningful value. They are themselves values, but they carry no information.

Front 19

Automatic type conversion || Type coercion

Back 19

When an operator is applied to the “wrong” type of value, JavaScript will quietly convert that value to the type it wants, using a set of rules that often aren’t what you want or expect. This is called type coercion