Why can't I concat an array reference in JavaScript? -


i have 2 arrays, 1 comes reference (parameter) function, , other created part of function - same scenario described here:

add 2 arrays without using concat method

i using push.apply() method per suggestion above, can please explain me, why can't use concat() merge 2 arrays if array sent function reference?

refer array.concat on mdn:

any operation on new array will have no effect on original arrays, , vice versa.

this makes behave differently array.push.apply will mutate original array object - return value of array.concat must used. otherwise, works explained in mdn link above.


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