159 lines
3.9 KiB
Markdown
159 lines
3.9 KiB
Markdown
---
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title: Arithmetic Operation
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---
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JavaScript provides five arithmetic operators: `+`, `-`, `*`, `/` and `%`. The operators are for addition, subtraction, multiplication, division and remainder, respectively.
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## Addition
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**Syntax**
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`a + b`
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**Caution**
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<br>
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The `+` serves as an arithmetic operator and for concatenating strings. Take extra caution when dealing with numbers versus string data types.
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If `a` and `b` data types are both numbers, their value will add.
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<br>
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If `a` is a number and `"b"` is a string, their value will concatenate into a string.
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<br>
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If `"a"` and `"b"` are both strings, their value will concatenate into a string.
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**Usage**
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2 + 3 // returns 5
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5 + "3" // returns "53"
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"10" + "40" // returns "1040"
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true + 2 // interprets true as 1 and returns 3
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false + 5 // interprets false as 0 and returns 5
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true + "bar" // concatenates the boolean value and returns "truebar"
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5 + "foo" // concatenates the string and the number and returns "5foo"
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"foo" + "bar" // concatenates the strings and returns "foobar"
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_Note:_ There is a handy [increment(++)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators#Increment) operator that is a great shortcut when you're adding numbers by 1.
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## Subtraction
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**Syntax**
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`a - b`
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**Usage**
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2 - 3 // returns -1
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3 - 2 // returns 1
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false - 5 // interprets false as 0 and returns -5
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true - 3 // interprets true as 1 and returns -2
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5 - "foo" // returns NaN (Not a Number)
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_Note:_ There is a handy [decrement(--)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators#Decrement) operator that is a great shortcut when you're subtracting numbers by 1.
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## Multiplication
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**Syntax**
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`a * b`
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**Usage**
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2 * 3 // returns 6
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3 * -2 // returns -6
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false * 5 // interprets false as 0 and returns 0
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true * 3 // interprets true as 1 and returns 3
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5 * "foo" // returns NaN (Not a Number)
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Infinity * 0 // returns NaN
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Infinity * Infinity // returns Infinity
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## Division
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**Syntax**
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`a / b`
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**Usage**
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3 / 2 // returns 1.5
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3.0 / 2.0 // returns 1.5
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3 / 0 // returns Infinity
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3.0 / 0.0 // returns Infinity
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-3 / 0 // returns -Infinity
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false / 5 // interprets false as 0 and returns 0
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true / 2 // interprets true a 1 and returns 0.5
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5 / "foo" // returns NaN (Not a Number)
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Infinity / Infinity // returns NaN
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## Remainder
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Also referred to as the "modulus" or "modulo" operator.
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**Syntax**
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`a % b`
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**Usage**
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3 % 2 // returns 1
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true % 5 // interprets true as 1 and returns 1
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false % 4 // interprets false as 0 and returns 0
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3 % "bar" // returns NaN
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## Increment
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**Syntax**
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`a++, ++a or a+=`
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**Usage**
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// Postfix
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x = 3; // declare a variable
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y = x++; // y = 4, x = 3
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// Prefix
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var a = 2;
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b = ++a; // a = 3, b = 3
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// Advanced
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var a = 4;
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var b = 5;
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a += b; //a = 9, b = 5
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## Decrement
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**Syntax**
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`a--, --a or a-=`
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**Usage**
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// Postfix
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x = 3; // declare a variable
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y = x--; // y = 3, x = 3
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// Prefix
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var a = 2;
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b = --a; // a = 1, b = 1
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// Advanced
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var a = 9;
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var b = 4;
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a -= b; //a = 5, b = 4
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_!Important!_ You **cannot** perform any sort of operations on `Infinity`.
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## Exponentiation
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**Syntax**
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`a ** b`
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**Usage**
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3 ** 2; // returns 9
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3 ** 0; // returns 1
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3 ** -Infinity; // returns 0
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_!Important!_ As you can see, you **cannot** perform any sort of operations on `Infinity`.
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Source: The amazing [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators)
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