Javascript - Logical Operator

OR, ||

Returns expr1 if it can be converted to true; otherwise, returns expr2. See Javascript - Boolean (Truthy|Falsy)

expr1 || expr2

Usage Example:

• Initialization even if it's a null object

x = null;
y = x || "x was null";
console.log(y)

Snippet example:

Example:

console.log('Return expression1')
console.log(true || 'expr2')
console.log(1 || 'expr2')
console.log('s' || 'expr2')
console.log('\n')
console.log('Return expression2')
console.log(false || 'expr2')
console.log(0 || 'expr2')
console.log('' || 'expr2')

&&

• true && expression always evaluates to expression
• false && expression always evaluates to false

Therefore, in a statement such as condition && expression, if the condition is true, the element right after && will appear in the output. If it is false, it will be ignored.