Beginning JavaScript Vocabulary
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
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| Array literals | The most common of which is to list values in a pair of square brackets
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| Accessing array elements | indexes start at 0 and increment by 1, so the first element's index is 0, the second element's index is 1, the third element's is 2, etc.
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| Multi-dimensional Arrays | A two-dimensional array is an array within an array. If you fill this array with another array you get a three-dimensional array and so on.
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| Array constructor | create an array
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| Accessing nested array elements | Accessing multi dimensional array elements is quite similar to one-dimension arrays . They are accessed by using [index][index]
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| Boolean literals | true or false syntax
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| Boolean logical operators | expression1 && expression2 //returns true if both the expressions evaluate to true
expression3 || expression4 // return true if either one of the expression evaluates to true
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| Comparison operators | x === y // returns true if two things are equal
x !== y // returns true if two things are not equal
x <= y // returns true if x is less than or equal to y
x >= y // returns true if x is greater than or equal to y
x < y // returns true if x is less tha
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| note | Boolean literals (true and false) assert truth or false
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| == vs. === | does just value checking ( no type checking ) , whereas , === does both value checking and type checking
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| Definition | Comments are like notes , suggestions , warnings ,etc. that you can put for yourself. Code comments are not executed
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| Single Line Comment | Anything on the line following // will be a comment while anything before will still be code.
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| Multi-Line Comment | Anything between /* and */ will be a comment.
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| console.log | Prints text to the console. Useful for debugging.
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| console.time | This function starts a timer which is useful for tracking how long an operation takes to happen
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| console.timeEnd | stops a timer that was previously started by calling console.time()
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| Function definition | To use a function, you must define it somewhere in the scope from which you wish to call it. A function definition (also called a function declaration) consists of the function keyword,
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| Function calling | functionName(Argument1,2,...
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| Function hoisting | Declaring a function one way "hoists" it to the top of the call, and makes it available before it's actually defined.
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| if | It simply states that if this condition is true , do this , else do something else ( or nothing ) . It occurs in varied forms.
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| else | A fallback to an if statement. This will only get executed if the previous statement did not.
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| else if | This is like an else statement, but with its own condition. It will only run if its condition is true, and the previous statement's condition was false.
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| For Loops | You use for loops, if you know how often you'll loop. The most often used varName in loops is "i".
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| While Loops | You use while loops, if you don't know how often you'll loop.
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| Do while loops | You use do while loops, if you have to loop at least once, but if you don't know how often.
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| random | Returns a random number between 0 and 1
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| floor | Returns the largest integer less than or equal to a number.
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| pow | Returns base raised to exponent.
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| ceil | Returns the smallest integer greater than or equal to a number.
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| PI | Returns the ratio of the circumference of a circle to its diameter, approximately 3.14159 or in better terms, the value of PI
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| sqrt | Returns the square root of a number.
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| % (Modulus) | it returns the remainder left after dividing the left hand side with the right hand side.
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| isNaN | Returns true if the given number is not a number , else returns false.
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| Basic Arithmetic | Doing basic arithmetic is simple. basic math
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| Prefix and Postfix increment/decrement operators | Prefix increment / decrement operators are operators that first increase the value of the variable by 1 (increment) or decrease the value of an expression / variable by 1 (decrement) and then return this incremented / decremented value
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| Object Literals | "property 1": value1,
property2: value2,
number: value3
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| Property Access | name1[string]
name2.identifier
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| Classes | A class can be thought of as a template to create many objects with similar qualities. Classes are a fundamental component of object-oriented programming (OOP).
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| Alert | Display an alert dialog with the specified message and an OK button. Note: The alert dialog should be used for messages which do not require any response on the part of the user,
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| Confirm | returns true if confirmed false otherwise
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| Prompt | The prompt() displays a dialog with an optional message prompting the user to input some text. If the user clicks the "Cancel" button , null is returned.
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| Strings | Strings are text. They are denoted by surrounding text with either single or double quotes.
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| Concatenation | string1+string2
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| Length | Returns the length of the string.
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| toUpperCase, toLowerCase | Changes the cases of all the alphabetical letters in the string.
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| trim() | Removes whitespace from both ends of the string.
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| replace() | Returns a string with the first match substring replaced with a new substring.
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| charAt() | Returns the specified character from a string. Characters in a string are indexed from left to right. The index of the first character is 0
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| substring() | Returns the sequence of characters between two indices within a string.
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| indexOf | Returns the index within the calling String object of the first occurrence of the specified value, starting the search at fromIndex, Returns -1 if the value is not found. The indexOf method is case sensitive.
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| switch | Checks a value against a list of cases, and executes the first case that is true.
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| Ternary Operator | The ternary operator is usually used as a shortcut for the if statement.
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| Variable Assignment | var name = value;
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| Variable changing | varname=newValue
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