JS logical operation

Non -!

Returns False if an operand is an object;

Returns true if an operand is an empty string;

Returns False if an operand is a non-empty string;

Returns true if an operand is a numeric value of 0;

Returns False if an operand is an arbitrary non-0 character;

Returns true if an operand is null;

Returns true if an operand is Nan;

Returns true if an operand is undefined;

Implicit conversion: ', 0,undefined,nan,false,null default conversion to FALSE! Time-varying to true

and &&

(1) For Boolean values, logic and is very simple, as long as there is a false, return false;

(2) For cases where the Boolean value is not true:

Returns a second number if the first operand is an object

If the second operand is an object, the object is returned only if the value of the first operand evaluates to true;

If the first two operands are objects, the second operand is returned

Returns null if one of the operands is null

If one of the operands is Nan, the first Nan is returned

Returns undefined if the first operand is undefined

or | |

(1) For Boolean values, logical or very simple, as long as there is a true, return true;

(2) For cases where the Boolean value is not true:

If the first operand is an object, the first operand is returned

Returns the second operand if the evaluation result of the first operand is false

If two operands are objects, the first operand is returned

Returns NULL if two operands are null

If two operands are Nan, a nan is returned

If two operands are undefined, the undefined is returned

JS logical operation