if ([] = = false) {console.log ("a")}
if ({} = = false) {console.log ("b")}
if ([] = = {}) {console.log ("c")}
if ([]) {console.log ("d")}
the way of implicit conversion of these questions, please help me to solve
if ([] = = false) {console.log ("a")}
if ({} = = false) {console.log ("b")}
if ([] = = {}) {console.log ("c")}
if ([]) {console.log ("d")}
the way of implicit conversion of these questions, please help me to solve
Equality comparison between objects and non-objects
ES5 specification 11.9.3.8-9 makes the following provisions:
if Type (x) is a string or number, Type (y) is an object, return the result of x = = ToPrimitive (y);
if Type (x) is an object, Type (y) is a string or number, return the result of ToPromitive (x) = = y.
ToPrimitive is to try to return its original value, that is, string or number .
therefore:
[] will first pass valueOf to get [] , which is not the original value, and then through toString to get "" .
"[object Object]"
''! = "[object Object]"
= , [] defaults to true reference: "JS (middle) you don't know" , it is strongly recommended to take a look, and give a very lame [=! [] , return true !
https://codeshelper.com/a/11.
the analysis of a master planing ancestral grave, you can take a hard look at
[], {} will be implicitly converted into true
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