Addition (+)
The addition operator (+) produces the sum of numeric operands or string
concatenation.
Syntax
x + y
Examples
Numeric addition
// Number + Number -> addition
1 + 2 // 3
// Boolean + Number -> addition
true + 1 // 2
// Boolean + Boolean -> addition
false + false // 0
String concatenation
// String + String -> concatenation
'foo' + 'bar' // "foobar"
// Number + String -> concatenation
5 + 'foo' // "5foo"
// String + Boolean -> concatenation
'foo' + false // "foofalse"
Specifications
| Specification |
|---|
| ECMAScript Language Specification # sec-addition-operator-plus |
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