Addition Is Not Working In JavaScript


Answer :

One or both of the variables is a string instead of a number. This makes the + do string concatenation.

'2' + 2 === '22';  // true  2 + 2 === 4;  // true

The other arithmetic operators / * - will perform a toNumber conversion on the string(s).

'3' * '5' === 15;  // true

A quick way to convert a string to a number is to use the unary + operator.

+'2' + 2 === 4;  // true

...or with your variables:

+x + +y

+ has two uses. One is addition, the other however is string concatenation. If one or both of your variables is a string, then + will concatenate them.

You will need to use parseInt or parseFloat to turn a string into a number.


In Javascript the + operator can either perform addition or concatenation depending on the type of its operands. When numbers are used with + it uses addition, but when strings are used with + it concatenates (joins the strings) instead


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