This operator is used to concatenate strings or sum the numbers: var result = "Hello, " + "World!"; // string + string = string (concatenation) // "Hello, World!" JavaScript allows to use objects, arrays, null or undefined as operands. How can I draw the surface f(x,y)=x^2+y^2 like my picture? Notice that this method will not mutate your original array, but will return a new one. In other words, an array is a unique variable that can hold more than a value at the same time. Why is it not recommended to install Windows after Ubuntu for dual-boot? Addition or concatenation is possible. Which way is better all depends on the situation. Whereas concat and spread will not and will instead return a new array. If the number is greater than 0, it evaluates to true. When working with JavaScript strings sometimes you need to join two or more strings together into a single string. Trouvé à l'intérieur – Page 80What might be intended to be an addition operation is interpreted as string concatenation through a combination of operator ... DOCTYPE HTML> Example