- 1 What does || mean in JS?
What does || mean in JS?
The Logical OR operator ( || ) is an operator that returns its first or second operand depending on whether the first is truthy. A “truthy” value means anything other than 0, undefined, null, “”, or false.
The left shift operator ( << ) shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.
A comparison operator compares its operands and returns a logical value based on whether the comparison is true. The operands can be numerical, string, logical, or object values. Strings are compared based on standard lexicographical ordering, using Unicode values.
An expression is any valid set of literals, variables, operators, and expressions that evaluates to a single value. The value may be a number, a string, or a logical value. Conceptually, there are two types of expressions: those that assign a value to a variable, and those that simply have a value.
The shift() method removes the first element from an array and returns that removed element. This method changes the length of the array.
If the browser returns undefined after each line of execution, its a statement. If the browser returns any value other than undefined after each line of execution, its an expression.