How to use the javascript equality operator
This article will explain in detail how to use the javascript equality operator. The editor thinks it is very practical, so I share it with you as a reference. I hope you can get something after reading this article.
1. Same type, basic type, compare whether the value is the same.
Object to compare whether the reference address is consistent.
{id: 1} = {id: 1} returns false. They have different references and are not an object.
2. Compare the string with the numeric value and convert it to Number.
3. Compared with the basic type, the object follows the above transformation rules to compare.
Let a = {}; a = = 0; return false, first valueOf returns {}, which is not equal to 0
4. Null is equal to undefined.
Note that null and undefined do not make any transformations when comparing them to each other.
That is, comparing undefined, null with 0, "", false, etc., all returns false.
NaN is equal to any data and returns false, while unequal comparison returns true.
Example
Console.log ('packt'?true:false); / / true string length is greater than 1console.log (' packt'==true) / / false/* first the Boolean value (true/false) is converted to a number by the toNumber method, so 'packt'==true is converted to' packt'==1. Second, the string value is converted with toNumber because if the string contains letters, it is converted to NaN, so the expression is converted to NaN==1 and the result is false * / console.log ('packt'==false); / / falseconsole.log (undefined==null) / / this is the end of the true article on "how to use the javascript equality operator". I hope the above content can be helpful to you, so that you can learn more knowledge. if you think the article is good, please share it for more people to see.
