If applied to boolean values, the&&operator only returnstruewhen both of its operands aretrue(andfalsein all other cases), while the||operator only returnsfalsewhen both of its operands arefalse(andtruein all other cases). Using Logical Operators with Non-Boolean Values# In JavaScript, the lo...
In JavaScript, logical operators are used for boolean logic where a boolean value may be returned depending on the outcome of an expression. With the || (OR) operator, since values don't need to be explicitly true or false (they can be truthy or falsy), the operator can return non-...
How does the logical AND operator work in Javascript In boolean contexts,&&simply returnstrueif all operands aretruthyortrue, andfalse, if any operand isfalsyorfalse. When I say boolean contexts, I am referring to situations wheretrueorfalseis expected, such as inif..elsestatements, or any s...
So we can conclude that if and only if, both of the conditions are TRUE or 1, LOGICAL AND operations returns TRUE or 1.Example: The following web document demonstrates the use of AND operator (&&).HTML Code<!doctype html> JavaScript logical AND operator example h1 { color:red; bor...
“Expected an operator and instead saw ‘{a}’.”:“需要用一个符号来代替’{a}’”, “Unexpected space after ‘{a}’.”:“在’{a}’之后不能出现空格”, “Unexpected space before ‘{a}’.”:“在’{a}’之前不能出现空格”, “Bad line breaking before ‘{a}’.”:“在’{a}’之前错...
5 === "5" // false JavaScript Copy In this case, the comparison returns false because the type of the two values is different. Here's an example of using the "===" operator in JavaScript: let num = 5; let str = "5"; if(num === str){ console.log("num and str are equal"...
Difference between =, ==, and === in JavaScript This guide clarifies the differences among =, == and === in JavaScript, with examples to demonstrate each operator. = (Assignment Operator): The = operator assigns a value to a variable. For instance, x = 5 assigns the value 5 to x....
所以OR 運算子有個用法是設定預設值。function foo (arg) { arg = arg || 'default' return arg // 根據運算子的規則, arg 如果不為 truthy value的話,就會是我們預設的 'default' }原理就是如此,如果想要判斷空字串跟0的話可以使用 Nullish coalescing operator 可以參考我之前寫的一篇文章。另外假設現在有...
1. JavaScript Equal To OperatorThe equal to operator == evaluates totrue if the values of the operands are equal. false if the values of the operands are not equal.For example,// same value, same type console.log(5 == 5); // true // same value, different type console.log(2 == ...
Are you baffled(阻碍;使迷惑) by thenewoperator in JavaScript? Wonder what the difference between a function and a constructor is? Or what the heck a prototype is used for? I’m going to lay it out straight. Now, there’s been a lot of talk for a long time about so-called “pseudo...