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What does “options = options || {}” mean in Javascript?
I have seen this in JS:
item = item || {}; I'm guessing it's some variation of a ternary operator but what does is actually do?
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The JavaScript Pipeline Operator ( |> ) is used to pipe the value of an expression into a function. This operator makes chained functions more readable. This function is called using ( |> ) operator and whatever value is used on the pipeline operator is passed as an argument to the function.
The double pipe operator (||) is the logical OR operator . In most languages it works the following way: If the first value is false, it checks the second value. If it's true, it returns true and if it's false, it returns false.
A single pipe is a bit-wise OR. Performs the OR operation on each pair of bits. a OR b yields 1 if either a or b is 1. JavaScript truncates any non-integer numbers in bitwise operations, so its computed as 0|0 , which is 0.
(expr1 || expr2) "Returns expr1 if it can be converted to true; otherwise, returns expr2."
source
So when expr1 is (or evaluates to) one of these 0,"",false,null,undefined,NaN, then expr2 is returned, otherwise expr1 is returned
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