The unary plus operator (`+`

) precedes its operand and evaluates to its operand but attempts to convert it into a number, if it isn't already.

Operator:+x

Although unary negation (`-`

) also can convert non-numbers, unary plus is the fastest and preferred way of converting something into a number, because it does not perform any other operations on the number. It can convert string representations of integers and floats, as well as the non-string values `true`

, `false`

, and `null`

. Integers in both decimal and hexadecimal (`0x`

-prefixed) formats are supported. Negative numbers are supported (though not for hex). Using the operator on BigInt values throws a TypeError. If it cannot parse a particular value, it will evaluate to `NaN`

.

const x = 1; const y = -1; console.log(+x); // 1 console.log(+y); // -1

+true // 1 +false // 0 +null // 0 +function(val){ return val } // NaN +1n // throws TypeError: Cannot convert BigInt value to number

Desktop | ||||||
---|---|---|---|---|---|---|

Unary plus (`+` ) |
1 | 12 | 1 | 3 | 4 | 1 |

Mobile | ||||||
---|---|---|---|---|---|---|

Unary plus (`+` ) |
1 | 18 | 4 | 10.1 | 1 | 1.0 |

Server | |
---|---|

Unary plus (`+` ) |
0.1.100 |

- Addition operator
- Subtraction operator
- Division operator
- Multiplication operator
- Remainder operator
- Exponentiation operator
- Increment operator
- Decrement operator
- Unary negation operator

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https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Unary_plus