clearly defines a variable, why output undefined.
" < " is the content of the command return that you enter. Define a variable that does not have return information
for example, you execute the following two commands in the console:
const a = () => 1 // areturnundefined
a() // areturn11declares that a variable will not return a value, and assigning a value to a variable will return the value itself
because the console attempts to print the result of an expression evaluation by default.
for example:
> 1 + 2
3 console tries to print the result of the expression evaluation 1x2 , so it displays 3
similarly, if you
> console.log(2)
2
undefined first the result of the expression is: print 2 (note that it is not return 2 but print 2), and then the console tries to print the calculated (return) result of console.log (). It does not return any results, so it displays undefined
so, I don't have to explain this.
var x = 8
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