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getify / You-Dont-Know-JS

A book series on JavaScript. @YDKJS on twitter.
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Small Change in Chapter 4 (Types and Grammar) #1649

Closed aditya-mitra closed 4 years ago

aditya-mitra commented 4 years ago

It is not just the second operand but the last operand which is returned when all the conditions are true for &&. Similarly, it is not just the second operand but the first operand, which is true, that is returned for ||.

var a =42; var b = "abc"; var c = null; var d = 1; var e = 0; a && b && d; //1 e || c || a; //42

getify commented 4 years ago

This book was published almost 5 years ago, so it's not subject to any changes at this point.

Moreover, you're changing the meaning of the text to refer to a different concept (operator associativity), which is dealt with elsewhere in the text.

For posterity, the current text uses "first" and "second" (operands) because the context of discussion is just one usage of || or &&. Your changes mix in the concept of multiple uses of the operator strung together. The way that works is the operators are still processed one at a time (so, still a "first" and "second" operand), and the order that the operators are handled is left-to-right because the || and && are left-associative.